SAT Reading and Writing Quiz: Inferences

20 questions · exam conditions

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InferencesQuestion 1 of 20

To reduce food waste, managers at a chain of campus cafes posted small signs at tray return stations reading 'Only take what you will eat.' Over eight weeks, the company alternated weeks with and without signs while keeping menus, hours, and staffing constant. On sign weeks, the cafeterias discarded an average of 310 pounds of leftovers per day; on no-sign weeks, 360. The pattern held at all six locations and did not coincide with holidays or special events. Waste was weighed at closing each night by the same staff. Because the schedule and menus were fixed across conditions, the main difference tracked was the presence of signage. Still, the observational design could not test why any change occurred. Therefore, .

Which choice most logically completes the text?

in these cafeterias during the study, days with signs coincided with less discarded food than days without signs

posting such signs will reliably reduce food waste at restaurants of every kind across the city

lower waste on certain days likely prompted managers to post the signs during those particular weeks

diners probably feel watched or judged whenever signs are posted near the tray return stations

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SAT Reading and Writing Quiz

SAT Reading and Writing Quiz: Inferences

Practice Inferences in SAT Reading and Writing with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Inferences, giving you a quick way to practice the rules, question types, and explanations that matter most for SAT Reading and Writing.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

Which choice most logically completes the text?

in these cafeterias during the study, days with signs coincided with less discarded food than days without signs (correct answer)
posting such signs will reliably reduce food waste at restaurants of every kind across the city
lower waste on certain days likely prompted managers to post the signs during those particular weeks
diners probably feel watched or judged whenever signs are posted near the tray return stations

Explanation: The passage compares waste on sign days (310 pounds) with no-sign days (360 pounds) but warns that the observational design can't reveal why. So the only warranted conclusion stays descriptive: during this study, days with signs went along with less discarded food than days without them. The choice about restaurants of every kind across the city overgeneralizes—the study covered only six campus cafes, not all restaurant types. The choice claiming lower waste prompted managers to post signs reverses the timing and cause: the signs were part of a planned alternating schedule, not a response to earlier waste. The choice about diners feeling watched or judged makes a claim about feelings the passage never measured; nothing in the data speaks to how diners reacted emotionally. Only the descriptive statement matches what the evidence can actually support.

Question 2

Agronomists tracked wheat yields over two seasons on matched fields within the same valley. Half the fields received a water-saving irrigation upgrade; half continued with existing systems. Rainfall was similar across the valley, fertilizer schedules were unchanged, and pest pressures were monitored and did not differ meaningfully between the groups. Yields increased on most upgraded fields relative to their own prior-season baselines, whereas yields on the non-upgraded fields showed no comparable gains. Local grain prices and contract terms were stable throughout the study. Taken together, these comparisons indicate that, within this setting, attributing the yield increases to some factor other than the irrigation change would disregard that .

Which choice most logically completes the text?

the upgrade will guarantee higher profits for every farmer working land elsewhere in the region
the upgrade was adopted only after yields on those particular fields had already begun climbing
the upgrade somehow caused rainfall to fall more evenly across the fields throughout the valley
the upgrade was the only recorded difference between the fields that gained and those that did not (correct answer)

Explanation: The passage controls for the obvious alternatives: rainfall, fertilizer, pest pressure, and market conditions were all similar or stable across the groups. The one thing that differed—and that lined up with where yields rose—was the irrigation upgrade. So blaming the gains on anything else would ignore that the upgrade was the only recorded difference between improving and non-improving fields. That is the best completion. The profit choice overreaches: the study measured yields on these valley fields, not profits for farmers elsewhere, and "guarantee" claims certainty the data never support. The adoption-timing choice reverses cause and effect, saying the upgrade followed yield gains, when the passage clearly compares fields to their own earlier baselines and shows gains after the change. The rainfall choice is a non sequitur: an irrigation system cannot redistribute rainfall, and the passage already states rainfall was similar valley-wide, so no such effect exists.

Question 3

Over four weeks, a high school tracked bus ridership for all morning routes. On eight rainy days, average ridership was 120 students; on the twelve dry days, it held steady at about 80. During the study period, the bus schedule, school start time, and route coverage remained unchanged, and the district ran no promotions. A preliminary report described the rainy-day spikes as evidence that more students are steadily turning to buses. However, the daily logs show that higher counts occurred only on days with precipitation, with dry-day ridership neither rising nor falling. Therefore, the data indicate .

Which choice most logically completes the text?

students are shifting toward buses across the whole year regardless of the weather conditions
the district needs to add more morning routes right away to handle the growing daily demand
the higher counts reflect rain-specific shifts rather than a steady upward trend in overall ridership (correct answer)
rain is making students dislike walking to school over the long term rather than just on wet days

Explanation: The logs show ridership rose only on rainy days, while dry-day counts stayed flat and every other condition (schedule, start time, routes, promotions) was unchanged. That pattern points to a weather-driven bump, not a general climb—so the best completion says the higher counts reflect rain-specific shifts rather than a steady upward trend. The choice claiming students are shifting toward buses across the whole year regardless of weather contradicts the flat dry-day numbers. The choice urging the district to add routes right away prescribes an action the data never justify, since demand only spikes when it rains. The choice saying rain makes students dislike walking over the long term invents a lasting cause the four-week study cannot support and confuses a short-term weather effect with a permanent attitude change.

Question 4

In a survey of 800 farms, adoption of a drought-resistant seed variety was highest among farms that had experienced severe drought in the past three years. In years with normal rainfall, average yields for adopters and non-adopters were statistically indistinguishable. During a drought year, adopters saw smaller losses on average than non-adopters. The study was observational rather than randomized, and marketing materials for the seed claim higher yields in all conditions. Based on this evidence alone, it follows that .

Which choice most logically completes the text?

adopting the seed is certain to protect a farm's profits during any future drought year
the occurrence of severe droughts is largely a consequence of the seed choices farmers make
the data do not demonstrate a yield increase for adopters under normal rainfall conditions (correct answer)
every specialty seed on the market fails to improve average yields in any growing condition

Explanation: The survey reports that in normal-rainfall years, adopters and non-adopters had statistically indistinguishable yields. That means the evidence simply does not show any yield advantage for the seed under normal conditions—which is exactly what the correct choice states. The claim that the seed is certain to protect profits during any drought overreaches: the data show smaller average losses, not guaranteed profits, and one guarantee cannot follow from an average. The idea that seed choices cause droughts reverses the direction of the relationship; farms adopted the seed because they had already faced drought, not the other way around. The sweeping claim that every specialty seed fails to help overgeneralizes far beyond this single seed and this single observational study, which examined only one variety. Because the study is observational and shows equal yields in normal years, only the statement about normal-conditions yields is fully supported.

Question 5

Laboratory tanks housing genetically similar coral fragments were maintained for three months at identical temperatures and light levels but at different pH levels. Fragments in lower-pH tanks deposited less calcium carbonate than those in higher-pH tanks, a result replicated across three trials. In the field, reefs exposed to naturally low-pH waters near volcanic vents show thinner annual growth bands than nearby reefs in normal-pH waters; the sites otherwise share comparable temperatures, nutrient levels, and species mixes. Together, these laboratory and field observations indicate a consistent relationship between seawater acidity and coral calcification, even when other environmental variables are held constant or matched. Given this pattern, it follows that .

Which choice most logically completes the text?

many marine organisms besides corals are likely to deposit less calcium carbonate as seawater pH falls
the reduced calcification observed in corals is likely to be driving the decline in surrounding seawater pH
fish populations at the low-pH reef sites are probably declining for reasons that have nothing to do with acidity
corals kept in or exposed to lower-pH water tend to deposit less calcium carbonate than those in higher-pH water (correct answer)

Explanation: The passage reports the same pattern in two settings: in tanks and near volcanic vents, corals in lower-pH water build less calcium carbonate, even when temperature, nutrients, and species are matched. So the safest conclusion is that corals in lower-pH water tend to calcify less than corals in higher-pH water. The choice about many other marine organisms overreaches: the evidence concerns only corals, so you cannot extend it to all calcifying species. The choice that reduced calcification drives down surrounding pH reverses the direction shown—pH was the manipulated or naturally varying condition, and calcification was the response, not the cause. The choice about fish populations declining for non-acidity reasons introduces a topic the passage never studies; nothing here measures fish or their causes of decline, so it is unsupported. Only the statement about corals depositing less calcium carbonate in lower-pH water matches both the lab and field results without adding claims the evidence cannot bear.

Question 6

City transportation planners analyzed data from a six-month pilot across all five districts. During alternating weeks, buses either ran twice as often with no other changes, fares were cut by 25 percent with schedules unchanged, or vehicles were upgraded with Wi-Fi and new seating. Ridership increased in every district only during the higher-frequency weeks, with gains ranging from 12 to 18 percent; fare-cut and amenity weeks yielded no statistically significant changes. The agency's stated objective for the next quarter is to maximize ridership growth using a single initiative it can afford to implement systemwide. Because the pilot controlled for weather, school calendars, and marketing, planners concluded that the observed ridership differences were caused by the interventions themselves. Therefore, to meet the objective most directly, the agency should .

Which choice most logically completes the text?

cut fares more deeply across the network, since affordability likely drives ridership more than service levels do
increase bus frequency across the network to raise ridership systemwide (correct answer)
invest in Wi-Fi and improved seating on every vehicle to attract riders through better amenities
combine all three interventions at once so that their separate effects can reinforce one another

Explanation: The pilot found that ridership rose consistently, by 12 to 18 percent, only during the higher-frequency weeks, and the agency wants the single affordable initiative that maximizes growth. Expanding service frequency is the one intervention the data show actually worked, so it best completes the text. Cutting fares more deeply fails because fare-cut weeks produced no significant change, so the claim that affordability drives ridership contradicts the results. Investing in Wi-Fi and seating fails for the same reason: amenity weeks also showed no significant gains, so better amenities are not supported as the cause of growth. Combining all three interventions fails the objective, which specifies a single initiative the agency can afford systemwide, and it would spend resources on two changes the pilot showed had no effect. Only expanding frequency matches both the evidence and the stated goal.

Question 7

Two identical greenhouses grew the same tomato variety for eight weeks. The only systematic difference was light spectrum: one used blue-rich LEDs, the other red-rich LEDs. Plants under blue light developed shorter internodes (the distances between leaves), yielding stockier plants, while those under red light were taller. At harvest, dried biomass per plant did not differ between groups, and both sets had received equal water, fertilizer, and temperature control. Because mass was equal despite height differences, the spectral change altered plant form without changing total growth under these conditions. Thus, relative to red light, blue light changed how stems elongated rather than how much plant matter was produced, which means that .

Which choice most logically completes the text?

differences in plant height in this experiment reflected stem elongation rather than differences in total biomass (correct answer)
blue light must improve photosynthetic efficiency compared with red light, resulting in the observed changes to plant form
red light most likely caused overheating that stunted biomass accumulation in the taller set of tomato plants
all crops grown commercially will end up shorter but equally massive whenever they are cultivated under blue light

Explanation: The passage says biomass per plant was equal in both groups while heights differed, and that blue light changed how stems elongated rather than how much matter was produced. So the only conclusion the text supports is that the height difference came from stem elongation, not from any difference in total biomass. The choice about photosynthetic efficiency invents a mechanism the passage never measures—equal biomass actually argues against one light producing more growth. The overheating claim also invents an unmeasured cause; temperature was held equal, so nothing points to red light overheating anything. The claim about all commercial crops overgeneralizes: the experiment tested one tomato variety under specific controlled conditions and cannot support a conclusion about every crop everywhere.

Question 8

Ten cities that adopted congestion pricing saw average rush-hour vehicle counts fall by about 15% within six months. Ten matched cities without the policy—similar in population, unemployment rate, fuel prices, and season—showed no comparable decline. None of the pricing cities expanded transit service during the study period, and sensitivity checks excluding a one-week transit strike in one city produced the same pattern. While the data cannot reveal long-term permanence, they do distinguish the short-term decreases from changes that would have affected both sets of cities similarly. Taken together, these patterns indicate .

Which choice most logically completes the text?

the reductions will likely persist permanently in every city that adopts a similar pricing policy in the future
the observed decreases are not fully explained by broad factors shared by the pricing and non-pricing cities (correct answer)
traffic in the pricing cities would probably have dropped by a comparable amount even without the new policy
the decline mainly reflects a rise in public transit use that offset the reduced number of private vehicles

Explanation: The matched non-pricing cities—alike in population, unemployment, fuel prices, and season—showed no comparable drop, so factors shared by both groups cannot by themselves account for the decline in the pricing cities. That points to the pricing policy as a distinguishing factor for the short-term decrease. The choice about permanent, universal persistence overreaches: the passage explicitly says the data cannot reveal long-term permanence, and it studies only ten cities. The choice claiming traffic would have fallen anyway is contradicted by the matched cities, which did not decline. The choice crediting a rise in transit use fails because none of the pricing cities expanded transit service, and a sensitivity check removing a transit strike left the pattern unchanged, so transit shifts are not what the data support.

Question 9

Researchers established 24 prairie plots in the same field: half were seeded with 14 native flowering species, half with a single native species. Plots were matched for size and placed equal distances from the nearest road; weather conditions were recorded. Over eight weeks, trained observers counted pollinator visits. Even on days when total bloom density was equal across plot types, the multi-species plots consistently drew more visits. No fertilizer or pesticide was used in any plot, and mowing schedules were identical. The only measured factor that reliably differed between plot types during observation was the number of plant species. Therefore, within this experimental setup, the higher pollinator visitation is best attributed to .

Which choice most logically completes the text?

lower levels of road noise reaching the multi-species plots during observation
pollinators gradually driving increases in floral diversity across the plots over time
a general tendency for added plant species to raise pollinator numbers across ecosystems
the greater diversity of plant species present in those plots (correct answer)

Explanation: The passage rules out every factor except one: plots were matched for size, distance from the road, mowing, and chemical use, and even bloom density was equal on the days compared. The one measured difference tied to more visits was how many plant species each plot held, so the greater diversity of plant species is the best-supported cause. The road-noise choice invents an unmeasured factor—distance to the road was held equal and noise was never recorded. The choice about pollinators driving diversity reverses the cause and effect the study describes; seeding, not the pollinators, set the number of species. The choice about a general tendency across ecosystems overreaches: this single experiment supports a conclusion only 'within this experimental setup,' not a claim about ecosystems in general. Only the plant-species diversity answer stays inside what the data actually show.

Question 10

After the city installed speed humps on Elm Street, average speeds fell and reported collisions there dropped compared with the same months of the prior year. During that period, police also increased patrols in the neighborhood. On adjacent Maple Street, where no humps were added, average speeds rose and collisions increased. The transportation department's summary acknowledges that some collisions appear to have shifted from Elm to Maple. Given these mixed changes and the simultaneous patrol increase, the available data do not isolate a single cause for the observed patterns. Nor do they track whether overall collisions across both streets declined. Therefore, based on the department's own figures, .

Which choice most logically completes the text?

dangerous driving throughout the entire city has effectively been eliminated by these measures.
the increase in police patrols is clearly the sole cause of every change observed on both streets.
the lower collision rate on Elm Street is what prompted police to add patrols in the neighborhood.
it cannot be concluded that the speed humps reduced the total number of collisions in the area. (correct answer)

Explanation: The figures show collisions shifting from Elm to Maple, and the department did not track whether combined collisions on both streets fell. Without that total, and with patrols increasing at the same time, you cannot credit the humps with an overall reduction—so the best completion is that this conclusion cannot be drawn. The claim that dangerous driving was eliminated citywide overreaches: the data cover only two streets, not the whole city. The claim that patrols are the sole cause ignores the department's own statement that no single cause can be isolated. The claim that Elm's lower collision rate prompted the patrols reverses the timeline; the passage never says the drop came first, so it invents a cause-and-effect the data don't support.

Question 11

To address declining visits, the Hawthorn Public Library extended its weekday hours from closing at 6 p.m. to closing at 9 p.m. three months ago. During the same period, the library did not add new programs, raise its advertising budget, or alter its loan policies. Check-in data show that daytime visits (9 a.m.–6 p.m.) have remained within 2% of their prior weekly average. By contrast, new evening check-in stations record roughly 600 additional visits per week between 6 and 9 p.m., a time window in which the library previously logged almost no traffic because it was closed. Staff schedules and door counters were calibrated before the change to ensure accurate counts. Therefore, the records establish that .

Which choice most logically completes the text?

The extended hours caused overall circulation of materials per patron to rise substantially during the week.
More people visited the library between 6 and 9 p.m. after the change than before it took effect. (correct answer)
Patrons who came in remained at the library longer during each individual visit once evening hours began.
Other libraries that decide to extend their evening hours will see comparable increases in attendance.

Explanation: The records track when people check in, and the evening stations logged about 600 extra visits per week during hours when the library used to be closed. That directly supports the conclusion that more people came between 6 and 9 p.m. after the change than before. The claim about circulation of materials rising per patron goes too far: counting visits tells you nothing about how many items each person borrowed. The claim that patrons stayed longer per visit is also unsupported—check-in counts measure arrivals, not how long anyone lingered. And predicting that other libraries will see comparable increases overreaches: the data describe only Hawthorn and cannot establish a general rule for every library. Only the statement about more evening visitors follows strictly from what the records measure.

Question 12

Six months after Riverton implemented a peak-hour congestion fee for driving into downtown, automated roadway counters recorded 12 percent fewer car entries during the fee window. During the same hours, transit agencies reported a ridership increase on lines serving downtown of nearly the same magnitude. Parking rates and public transit schedules were unchanged, and the fee applied only during weekday rush periods. Meanwhile, data from door-mounted sensors at major downtown buildings showed overall visitor counts holding steady relative to the same months the previous year. With total visits stable, car trips down, and transit use up during the specific hours the fee was in effect, the evidence most directly supports the conclusion that .

Which choice most logically completes the text?

at least some former drivers used transit instead during the fee hours. (correct answer)
the fee reduced traffic congestion during the evening and overnight hours it did not cover.
the rise in transit ridership was what prompted the city to adopt the congestion fee.
downtown businesses saw a measurable increase in profits during the fee period.

Explanation: Visitor counts stayed steady while car entries fell and transit ridership rose by nearly the same amount during the exact hours the fee applied. If the same number of people kept visiting downtown but fewer arrived by car and more arrived by transit, some of those people must have shifted from driving to transit, so the best completion is that at least some former drivers used transit instead. The choice about evening and overnight hours fails because the fee, and all the data, covered only weekday rush periods—nothing supports claims about uncovered hours. The choice about ridership prompting the fee reverses the timeline: the fee came first, and higher ridership followed it, so ridership could not have caused it. The choice about business profits fails because the sensors measured visitor counts, not spending or profit, so there is no evidence about how much money businesses made.

Question 13

At a riverside archaeological site, researchers excavated a clay-lined hearth dated to about 4000 BCE. Inside the hearth they found a dense concentration of charred seed coats and starchy plant fragments, along with residue analyses indicating plant oils; nearby refuse pits yielded abundant plant processing tools. In the same layer, animal bones were present but lacked cut marks or burning, and none were found within the hearth itself. Radiocarbon dates from the seeds match the hearth's charcoal. Trade items in adjacent contexts suggest the community exchanged goods with distant groups, but they do not speak to the contents of this feature. Given the co-location of plant remains and plant residues in the hearth and the absence of animal-processing evidence there, it follows that .

Which choice most logically completes the text?

the animal bones in the layer were the remains of food cooked in this particular hearth.
the trade goods in nearby contexts were acquired specifically to obtain metal cooking implements.
the meal prepared in that hearth relied primarily on plant ingredients. (correct answer)
the plant processing tools in the refuse pits were used mainly to prepare animal foods.

Explanation: The hearth held charred plant remains and plant-oil residues but no cut, burned, or interior animal bones, so the food cooked there was mostly plant-based. That makes the choice about a plant-based meal the strongest inference. The claim that the animal bones were cooked in this hearth contradicts the passage, which notes those bones lacked burning or cut marks and were not found inside the hearth. The claim about trade goods obtaining metal implements is unsupported: the passage states the trade items say nothing about this feature's contents. The claim that the plant processing tools prepared animal foods misreads the tools' purpose and ignores the plant remains found with them.

Question 14

A city museum extended its closing time from 5 p.m. to 8 p.m. for one month. Ticket scans showed total daily visitors averaged 1,200 both before and after the change. However, the share of visitors arriving after 5 p.m. rose from 5 percent to 30 percent, while morning arrivals dropped by a similar amount. Admission prices, special exhibits, and marketing remained the same during the period. Staff noted that midday crowding eased slightly as arrivals spread across more hours. The scheduling change thus affected when many people chose to visit without altering overall demand for admission. Therefore, the effect of extending hours was primarily to .

Which choice most logically completes the text?

shift the timing of visits across more hours of the day (correct answer)
boost daily revenue through added evening ticket surcharges
lower morning demand, which then prompted the schedule change
draw visitors away from competing attractions across the city

Explanation: The data show that total daily visitors stayed at 1,200 while the share arriving after 5 p.m. jumped and morning arrivals fell by a similar amount, with crowds spreading across more hours. So the extended hours changed the timing of visits, not the number—making "shift the timing of visits across more hours of the day" the best fit. The evening-surcharge option fails because the passage says prices stayed the same and never mentions surcharges or revenue. The morning-demand option reverses cause and effect: the drop in morning arrivals followed the schedule change; it did not cause it. The competing-attractions option makes a broad claim the passage never supports—there is no comparison to other attractions, and total demand was unchanged, so nothing suggests the museum pulled visitors from elsewhere.

Question 15

In January, the Riverside Museum introduced two weekday-only changes: admission dropped from $15 to $10, and closing time moved from 5 p.m. to 8 p.m. All marketing budgets, exhibitions, and weekend prices and hours remained the same as in the previous year. Over the next three months, weekday attendance rose 18 percent compared with the same period last year, while weekend attendance was essentially unchanged. Gift-shop sales per visitor and average visit length were stable across all days. A voluntary exit survey indicated that many first-time weekday visitors mentioned "after-work convenience," while others cited "affordability," but the survey was not administered on weekends. Given that both changes took effect simultaneously and only on weekdays, the museum can conclude that .

Which choice most logically completes the text?

the extended evening hours, rather than the lower admission price, were what actually drove the weekday attendance increase.
the data collected cannot show whether the lower admission price or the later closing time drove the weekday attendance increase. (correct answer)
cutting admission prices is a dependable way to increase visitor attendance at museums generally.
the rise in weekday attendance is what led the museum to lower its price and extend its hours.

Explanation: Both weekday changes—the lower price and the later closing time—happened at the same time, while weekends (which changed in neither way) stayed flat. Because the two changes are bundled together, you cannot tell which one is responsible for the 18 percent jump, so the honest conclusion is that the data can't separate their effects. The choice naming extended hours as the true cause picks one factor with no evidence that isolates it; the exit survey even shows visitors citing both convenience and affordability. The choice about price cuts being dependable overgeneralizes from a single museum to museums everywhere. The choice claiming higher attendance caused the museum to change price and hours reverses the timeline—the changes came first, in January, and attendance rose afterward. Only the option that refuses to assign a single cause fits the evidence.

Question 16

To measure the effect of latency on purchasing, an online retailer randomly assigned 10 percent of browsing sessions a server-side delay of 200 milliseconds while leaving site content, prices, and promotions unchanged; another 10 percent were flagged but experienced no delay. Traffic levels and marketing campaigns remained steady throughout the test week. Sessions that received the injected delay had a 3 percent lower checkout completion rate than comparable undelayed sessions, while average order value among those who did purchase was the same across groups. The flagged-but-undelayed group behaved like the control. Because the assignment was random and the delay was the only difference, the delay can be isolated as the cause of the completion gap. These findings most directly support the conclusion that .

Which choice most logically completes the text?

The reduced checkout completion during delayed sessions probably lowered the average order value recorded for that group.
The lower completion rate observed in delayed sessions was most likely what caused the retailer's servers to respond more slowly.
The injected 200 ms delay caused a small reduction in checkout completion for the affected sessions. (correct answer)
The delay reduced completion during this test, so faster pages likely raise per-order spending for most online retailers.

Explanation: The study randomly assigned the 200 ms delay and used a flagged-but-undelayed group as a placebo, so the only difference between groups was the added delay. That design lets you isolate the delay as the cause of the 3 percent drop in checkout completion, which is exactly what the best answer states. The choice claiming the delay also lowered average order value contradicts the passage, which says order value was the same across groups. The choice saying low completion made the servers slow down reverses cause and effect—the delay was injected on purpose, not produced by shopper behavior. The choice about faster pages raising per-order spending for most retailers overreaches: order value did not change here, and one retailer's week-long test cannot support a claim about e-commerce in general. Only the statement tying the measured delay to a small completion drop stays inside what the data show.

Question 17

At Riverside University, librarians compared the first-month database logins of 400 first-year students. Of the 200 who completed a 30-minute database tour during orientation week, 88% logged into at least one research database before October; of the 200 who skipped the tour, 42% did so. The groups had comparable average high school GPAs and took similar numbers of credits, and the library offered no other research workshops that month. Login timestamps were recorded automatically by the subscription platforms. Because tour attendance was the only systematically measured difference between the groups, the records show a consistent association between attending the tour and early database use, so .

Which choice most logically completes the text?

In this sample, students were more likely to attend the tour because they already had a stronger initial interest in using research databases.
In this sample, tour attendees were more likely to log into research databases in the first month than were students who skipped the tour. (correct answer)
In this sample, students who skipped the tour were unlikely to develop any interest in research databases later in the academic year.
In this sample, attending the tour was likely the factor that directly raised students' course grades during their first academic term.

Explanation: The records track only who attended the tour and who logged in early, and they show a clear gap: 88% of attendees logged in versus 42% of non-attendees. The best completion simply restates that measured association—attendees were more likely than non-attendees to log into databases in the first month. The choice about a 'stronger initial interest' causing attendance reverses the direction of the relationship; the passage measured attendance and logins, not what motivated students to attend. The claim that non-attendees were unlikely to develop interest 'later in the academic year' reaches beyond the recorded period, which only covers the first month. The claim about the tour raising 'course grades' introduces an outcome no one measured—the data are about database logins, not grades. Only the statement that restates the observed first-month association stays within what the records actually support.

Question 18

During excavation at a farmhouse site, archaeologists uncovered a compact hearth sealed by ash dated to about 1250. Directly beneath the hearth, embedded in undisturbed soil, lay three coins issued under a ruler known to have begun minting no earlier than 1200. Stratigraphic notes documented no burrows or intrusive features cutting through the hearth into the coin-bearing layer; the only disturbance was a small animal tunnel above the ash. Because the coins were physically below the hearth and the layers were intact, the coins must have been deposited before the hearth was built. Because the coins themselves cannot predate 1200, their deposition is bounded on both sides by independent evidence. Therefore, the coins were most likely deposited .

Which choice most logically completes the text?

by the hearth's builders to mark the start of construction, once the site had been leveled.
at the same moment the hearth was raised and then gradually pressed downward into the soil.
well before the year 1200, a timing shown by their position beneath the hearth's ash layer.
after 1200 but before the hearth was established near 1250, within that bracketed window. (correct answer)

Explanation: The intact layers prove the coins were placed before the hearth, which is dated to about 1250, so their deposition cannot be later than that. The coins also cannot predate 1200, since that ruler minted nothing earlier. Together these limits bracket the deposition to the span after 1200 and before the hearth—so the correct choice names that window. The option placing the coins well before 1200 ignores the minting constraint: the coins simply could not exist before that year. The option crediting the hearth's builders with marking construction contradicts the finding that the coins lie in undisturbed soil below the hearth, meaning they were already there when building began. The option claiming the coins were laid at the same moment as the hearth and then pressed downward is ruled out by the stratigraphic notes, which record no intrusive features—nothing disturbed the layers to sink the coins. Only one choice respects both independent limits at once.

Question 19

Technical imaging of a small portrait revealed an underdrawing that matches the artist's characteristic hatching and corrections, and dendrochronology dated the wood panel to a year the artist is documented to have spent in the city where the sitter lived. An archival ledger notes the artist taking a commission that month from the sitter's family. A painted signature, however, was applied in a different pigment layer that cross-cuts aging craquelure consistent with a later dealer's touch-ups. Therefore, any argument for attributing the portrait to the artist should rely on the underdrawing and archival timing rather than on .

Which choice most logically completes the text?

the dealer's undocumented claim that he watched the artist sign the finished portrait himself
a broad assumption that a painted signature can never be a reliable indicator of who made a work
an inscription introduced only once the completed painting had already passed out of the artist's hands (correct answer)
recent auction prices commanded by portraits produced elsewhere by the artist's wider circle of followers

Explanation: The passage shows the signature sits in a separate pigment layer cutting across aging craquelure, meaning it was added long after the artist finished the work—so a mark added after the painting left his hands cannot prove he made it. That is exactly why an attribution should rest on the underdrawing and archival timing instead. The dealer's claim that he watched the artist sign it is undocumented and self-serving, so it carries no evidentiary weight. Treating a painted signature as never reliable overgeneralizes; the passage faults this signature for physical reasons, not signatures as a category. Recent auction prices for works by the artist's circle concern market value, not who painted this particular portrait, so they are irrelevant to attribution.

Question 20

The campus learning center tested whether private 'quiet rooms' improve immediate study performance. Over two weeks, 120 volunteers were randomly assigned to either a quiet room or the open reading hall for a single 50-minute session. Participants completed the same set of timed logic problems at the end of the session; proctors scored answers and recorded completion times. On average, the quiet-room group solved more problems correctly and finished sooner than the open-hall group. No other study supports, cues, or time limits differed by condition, and students did not choose their location. Because assignment was random and procedures were identical aside from the room type, the difference in outcomes can be attributed to the setting. Therefore, for this experiment, .

Which choice most logically completes the text?

access to a quiet room caused better performance on the timed logic task than studying in the open hall. (correct answer)
installing quiet rooms across the entire campus would reliably raise students' semester grade point averages.
the faster, higher-scoring students had deliberately chosen to work in the quieter rooms during the session.
quiet rooms are universally superior to every other possible study environment for all kinds of academic tasks.

Explanation: Because students were randomly assigned and the only difference between conditions was the room, the better scores and faster times can be traced to the setting itself. That is exactly what the correct choice states: the quiet room caused the improved performance on this task. The choice about raising semester GPAs stretches a single 50-minute session into a long-term, campus-wide outcome the study never measured. The choice claiming that faster, higher-scoring students chose the quiet rooms contradicts the passage, which says assignment was random and students did not pick their location. The choice calling quiet rooms 'universally superior' for all tasks overgeneralizes far beyond one timed logic test in one experiment. Only the first choice matches what the design actually supports.