GRE Quiz: Weaken Argument
19 questions · exam conditions
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Weaken ArgumentQuestion 1 of 19

A public health department concludes that a new advertising campaign caused a recent increase in flu vaccinations. The department notes that in the month after the campaign began, the number of vaccinations administered at local clinics rose by 15% compared with the previous month. The department therefore plans to run the same campaign every year to raise vaccination rates. Which of the following, if true, most weakens the argument?

The campaign's advertisements were placed primarily on social media platforms used heavily by younger adults.
In the same month the campaign began, several large employers in the area began requiring proof of flu vaccination for on-site work.
Some clinics reported that they temporarily ran out of a particular brand of flu vaccine.
The department's overall budget for health education is higher this year than it was five years ago.
The campaign did not include advertisements in languages other than English.
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GRE Quiz

GRE Quiz: Weaken Argument

Practice Weaken Argument in GRE 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 Weaken Argument, giving you a quick way to practice the rules, question types, and explanations that matter most for GRE.

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

A public health department concludes that a new advertising campaign caused a recent increase in flu vaccinations. The department notes that in the month after the campaign began, the number of vaccinations administered at local clinics rose by 15% compared with the previous month. The department therefore plans to run the same campaign every year to raise vaccination rates. Which of the following, if true, most weakens the argument?

  1. The campaign's advertisements were placed primarily on social media platforms used heavily by younger adults.
  2. In the same month the campaign began, several large employers in the area began requiring proof of flu vaccination for on-site work. (correct answer)
  3. Some clinics reported that they temporarily ran out of a particular brand of flu vaccine.
  4. The department's overall budget for health education is higher this year than it was five years ago.
  5. The campaign did not include advertisements in languages other than English.

Explanation: This question tests your ability to weaken an argument attributing increased flu vaccinations to an advertising campaign. To weaken this causal claim, you need to identify another factor that could explain the 15% increase. The health department assumes their campaign caused the increase and plans to repeat it annually based on this assumption. The Borrect answer (B) provides a powerful alternative explanation: several large employers began requiring proof of flu vaccination for on-site work in the same month. This mandate would naturally drive vaccination rates up regardless of any advertising campaign, seriously undermining the conclusion that the campaign deserves credit. Choice A about social media placement describes the campaign's method but doesn't weaken the causal claim, while choice C about temporary vaccine shortages might actually suggest the campaign was too successful rather than weakening it.

Question 2

A museum director argues that extending the museum's hours to include Friday evenings will increase annual attendance. The director cites a three-month trial in which Friday-evening attendance averaged 400 visitors per night, and notes that the museum's daytime attendance did not decline during the trial. The director concludes that making Friday-evening hours permanent will add those visitors to the annual total and will therefore increase ticket revenue. Which of the following, if true, most weakens the argument?

  1. During the trial period, the museum hosted a popular temporary exhibition that ended shortly after the trial concluded. (correct answer)
  2. Some museum employees prefer working evening shifts to working early-morning shifts.
  3. The museum's café experienced higher sales on Friday evenings during the trial.
  4. A nearby theater also offers discounted tickets on Friday evenings.
  5. The museum's annual membership program includes unlimited daytime admission.

Explanation: This question tests weakening an argument that permanent Friday evening hours will increase annual museum attendance and revenue. To weaken this conclusion, you need evidence suggesting the trial results won't translate to permanent increases. The director assumes that the 400 visitors per Friday evening represent new, additional attendance that will continue indefinitely. The Aorrect answer (A) reveals that a popular temporary exhibition was running during the trial and ended shortly after, suggesting that the high Friday evening attendance may have been driven by this special exhibition rather than the extended hours themselves. This means making the hours permanent might not sustain those attendance levels once the exhibition is gone. Choice C about café sales actually supports the extended hours, while choice D about nearby theater discounts doesn't explain why the trial attendance wouldn't continue.

Question 3

A university committee argues that because students in sections of Introductory Statistics that used weekly low-stakes quizzes earned higher final exam scores than students in sections without weekly quizzes, the university should require weekly quizzes in all large introductory courses to improve learning outcomes. The committee's reasoning assumes that the quizzes themselves caused the score increase and that similar effects will occur across other subjects. Which of the following casts the most doubt on the argument?​

  1. In the statistics course, the sections with weekly quizzes were taught by instructors with, on average, more years of teaching experience than instructors of sections without quizzes. (correct answer)
  2. Some students report that weekly quizzes increase stress, even when each quiz counts for a small portion of the grade.
  3. Several departments already use occasional quizzes, though not on a weekly schedule.
  4. The final exam in Introductory Statistics includes questions that closely resemble those on the weekly quizzes.
  5. Students in many large introductory courses attend optional review sessions before major exams.

Explanation: This question tests weakening an argument about educational interventions. To weaken means to provide evidence that the conclusion doesn't necessarily follow from the premises. The committee assumes that weekly quizzes caused the higher exam scores and that this effect will transfer to other subjects. The vulnerability in this reasoning is the assumption that the quizzes themselves, rather than other factors, produced the improvement. Answer A seriously weakens the argument by introducing a confounding variable: instructors with more teaching experience taught the sections with weekly quizzes. This suggests that instructor quality, not the quizzes, may have caused the higher scores, undermining the committee's conclusion about requiring quizzes universally. Answer D, about exam questions resembling quiz questions, actually strengthens rather than weakens the argument by providing a mechanism for how quizzes might improve scores.

Question 4

A manufacturer proposes replacing its current packaging with a lighter material, noting that a pilot test on one product line reduced shipping costs by 6% over three months. The manufacturer concludes that switching all product lines to the lighter packaging will reduce the company's total shipping costs by at least 6% annually. The proposal assumes that the pilot test results will generalize across products and time. Which of the following, if true, most weakens the argument?​

  1. The lighter packaging is made from a material that some customers perceive as less premium than the current packaging.
  2. During the pilot test, fuel surcharges imposed by the company's main carrier temporarily decreased, lowering shipping costs for all shipments regardless of packaging. (correct answer)
  3. The pilot product line accounts for a small share of the company's total annual shipments by weight.
  4. The lighter packaging costs slightly more per unit than the current packaging.
  5. Some product lines are shipped primarily to international destinations rather than domestic ones.

Explanation: This question asks you to weaken an argument about packaging and shipping costs. Weakening involves finding information that challenges the reasoning or introduces factors that undermine the conclusion. The manufacturer assumes that the 6% cost reduction in the pilot test was due to the lighter packaging and will generalize across all products and time periods. The critical assumption is that no other factors influenced shipping costs during the pilot. Answer B most effectively weakens the argument by revealing that fuel surcharges temporarily decreased during the pilot test, lowering all shipping costs regardless of packaging. This means the 6% reduction may have been due to external market conditions rather than the packaging change, seriously undermining the conclusion about future savings. Answer D, about higher packaging costs, addresses total costs but doesn't challenge the specific claim about shipping cost reduction.

Question 5

A beverage company tested a new label design on its bottled tea in two regions and found that sales in those regions rose by 8% compared with the previous quarter. The company concludes that the new label design increases consumer purchases and decides to roll out the label nationwide. The company notes that the tea's price and formula were unchanged and that the regions tested are representative of the national market. Which of the following casts the most doubt on the argument?

  1. In the test regions, the company also secured additional shelf space at several large retailers during the same quarter. (correct answer)
  2. Some consumers report that they prefer label designs that use fewer colors than the new design.
  3. The company's bottled tea is sold in more flavors nationwide than in the two test regions.
  4. The new label design costs slightly more per bottle to print than the old label design.
  5. Sales of bottled water in the test regions fell slightly during the same quarter.

Explanation: This question tests weakening an argument about a new label design causing increased tea sales. To weaken this argument effectively, you must identify information that suggests another factor could explain the 8% sales increase. The company assumes the label design alone drove sales, controlling for price and formula. The Aorrect answer (A) reveals that the company also secured additional shelf space at large retailers in the test regions during the same period. More shelf space typically leads to increased visibility and sales, providing an alternative explanation for the sales boost that has nothing to do with the label design. This seriously undermines the conclusion about rolling out the label nationwide. Choice D about higher printing costs addresses profitability rather than causation, while choice E about bottled water sales is irrelevant to whether the tea label caused increased tea sales.

Question 6

A city's transportation office reports that after installing adaptive traffic-signal software on three major corridors last year, average commute times on those corridors fell by 12%. The office concludes that expanding the same software to all intersections citywide will reduce overall city commute times by a similar amount. The office notes that the three corridors were selected because they are among the busiest in the city and argues that improvements there indicate the software's effectiveness in general. Which of the following, if true, most weakens the argument?

  1. Several neighborhoods not located near the three corridors have recently requested additional pedestrian crossings at intersections.
  2. During the year the software was installed, a major employer on one of the three corridors shifted 30% of its workforce to remote work, reducing peak-hour traffic volume on that corridor. (correct answer)
  3. The adaptive software requires annual licensing fees that are higher than the fees for the city's current signal-timing system.
  4. On a few minor streets that intersect the three corridors, drivers reported slightly longer waits at red lights after the software was installed.
  5. In a nearby city, a different brand of adaptive traffic-signal software produced mixed results when first introduced.

Explanation: This question tests your ability to weaken an argument about the effectiveness of adaptive traffic-signal software. Weakening an argument means finding information that reduces support for the conclusion that expanding the software citywide will reduce overall commute times. The argument assumes that the 12% improvement on three corridors occurred because of the software itself, not due to other factors. The Borrect answer (B) undermines this assumption by revealing that a major employer shifted 30% of its workforce to remote work on one corridor, which would naturally reduce traffic and commute times regardless of the software. This alternative explanation for the improvement suggests the software may not be as effective as claimed. Choice A about pedestrian crossings is irrelevant to the software's effectiveness on traffic flow, while choice C about licensing fees doesn't address whether the software actually works.

Question 7

A coastal town proposes building a seawall to prevent future flood damage. Town officials argue that because a smaller seawall built near the harbor five years ago has not been overtopped during storms since its construction, a larger seawall along the entire coastline will protect residential areas as well. They conclude that investing in the seawall is the most effective way to reduce flood-related repair costs over the next decade. Which of the following, if true, most weakens the argument?

  1. Some residents prefer nature-based solutions, such as restoring dunes, to large infrastructure projects.
  2. The harbor area where the existing seawall was built is sheltered by offshore rock formations, while much of the town's coastline is fully exposed to open-ocean waves. (correct answer)
  3. The proposed seawall would require periodic maintenance to address corrosion from saltwater exposure.
  4. Property values in the town have increased over the past five years.
  5. During the past decade, the town has spent more on road repairs than on flood repairs.

Explanation: This question asks you to weaken an argument that a larger seawall will protect the entire coastline based on a smaller harbor seawall's success. Weakening requires showing why the harbor's success might not translate to the broader coastline. The officials assume that because the harbor seawall hasn't been overtopped in five years, a similar structure will work equally well everywhere along the coast. The Borrect answer (B) reveals a crucial difference: the harbor is sheltered by offshore rock formations while much of the coastline faces open-ocean waves. This means the harbor seawall faced much less severe conditions than a coastal seawall would face, making the comparison invalid and seriously undermining the conclusion. Choice A about resident preferences doesn't address effectiveness, while choice C about maintenance needs doesn't challenge whether the seawall would actually prevent flooding.

Question 8

A hospital introduced a new scheduling system intended to reduce patient wait times in its outpatient clinic. After implementation, the average reported wait time fell from 46 minutes to 34 minutes. The hospital administrator concludes that the scheduling system is responsible and recommends adopting it in all hospital departments that schedule appointments. The administrator adds that the clinic's staffing levels remained constant, so the scheduling change must explain the improvement. Which of the following, if true, most weakens the argument?

  1. Some patients in the outpatient clinic prefer to arrive early even when appointments are scheduled later in the day.
  2. The outpatient clinic began sending automated reminder messages that reduced last-minute cancellations.
  3. During the same period, the clinic reduced the number of appointment slots per day by lengthening the standard appointment duration. (correct answer)
  4. Several departments in the hospital use different electronic medical record systems than the outpatient clinic uses.
  5. The new scheduling system requires staff training that takes several hours to complete.

Explanation: This question asks you to weaken an argument attributing reduced wait times to a new scheduling system. Weakening requires finding evidence that something other than the scheduling system could explain the improvement from 46 to 34 minutes. The administrator assumes that because staffing remained constant, the scheduling system must be responsible for the change. The Correct answer (C) provides a compelling alternative explanation: the clinic reduced the number of appointment slots by lengthening appointments, which would naturally reduce congestion and wait times regardless of the scheduling system. This directly undermines the conclusion that the scheduling system deserves credit and should be adopted elsewhere. Choice B about reminder messages might help with efficiency but doesn't directly explain shorter wait times, while choice E about training requirements doesn't address whether the system actually works.

Question 9

A regional electric utility claims that offering customers a rebate for installing smart thermostats will reduce peak electricity demand enough to avoid building a new substation. The utility bases this conclusion on a small pilot program in which participating households used 10% less electricity during peak hours than they had the previous summer. The utility argues that because peak demand is driven largely by residential air-conditioning use, expanding the rebate program will produce similar reductions at scale. Which of the following, if true, most weakens the argument?

  1. Some households in the pilot program reported that they liked being able to control their thermostat from a phone app.
  2. Commercial buildings account for a substantial portion of the region's peak electricity demand, and their demand has been rising faster than residential demand. (correct answer)
  3. The rebate amount is larger than rebates offered by neighboring utilities for similar devices.
  4. The smart thermostats in the pilot program were manufactured by several different companies.
  5. The utility's customer satisfaction ratings improved slightly after the pilot program began.

Explanation: This question asks you to weaken an argument about smart thermostats reducing peak electricity demand enough to avoid building a new substation. Weakening requires showing that the conclusion doesn't follow from the evidence about residential reductions. The utility assumes that because residential air-conditioning drives peak demand, a 10% household reduction will scale up to avoid needing new infrastructure. The Borrect answer (B) undermines this by revealing that commercial buildings account for a substantial portion of peak demand and their demand is rising faster than residential. This means that even if the residential program succeeds, it may not reduce overall peak demand enough to avoid the substation, since commercial demand isn't addressed. Choice A about customer preferences doesn't address whether the program reduces demand sufficiently, while choice C about rebate amounts compared to other utilities is irrelevant to effectiveness.

Question 10

A school district piloted a new mathematics curriculum in five middle schools and observed that, after one year, the average math test score in those schools increased by 6 percentage points. The superintendent concludes that adopting the curriculum in all district middle schools will raise math scores districtwide. The superintendent notes that the pilot schools include a range of socioeconomic backgrounds and that teachers received the same amount of training as usual. Which of the following statements most seriously undermines the conclusion?

  1. Several teachers in nonpilot schools have expressed interest in using supplemental online practice tools.
  2. The pilot schools replaced several retiring math teachers with newly hired teachers during the pilot year.
  3. The district's science test scores remained roughly constant during the same year.
  4. The pilot schools administered a different version of the math test than they had used the previous year, and the new version was designed to be easier for students at that grade level. (correct answer)
  5. The new curriculum includes more word problems than the previous curriculum did.

Explanation: This question tests your ability to weaken an argument about a new mathematics curriculum improving test scores. To weaken effectively, you need to identify factors other than the curriculum that could explain the 6-point increase. The superintendent assumes the curriculum caused the improvement and will produce similar results districtwide. The Dorrect answer (D) severely undermines this by revealing that the pilot schools used an easier version of the test, which would naturally produce higher scores regardless of curriculum quality. This alternative explanation suggests the curriculum may not be responsible for the improvement at all. Choice B about new teachers is somewhat relevant but doesn't clearly explain higher scores, while choice C about science scores is irrelevant to whether the math curriculum works.

Question 11

A university library replaced most staffed service desks with self-checkout kiosks. In the semester after the change, the library recorded a 20% increase in the number of items checked out. The library director concludes that the kiosks caused the increase and therefore plans to remove the remaining staffed desks to further boost circulation. The director adds that students prefer faster transactions and that kiosks provide them. Which statement most seriously undermines the author's conclusion?

  1. In the same semester, the library extended its operating hours by two hours per day on weekdays.
  2. Some students have complained that the kiosks occasionally fail to read older barcode labels.
  3. The library's budget for purchasing new books was slightly lower than in the previous year.
  4. The library offers study rooms that can be reserved online without interacting with service-desk staff.
  5. During that semester, several large introductory courses assigned weekly readings available only as physical reserves in the library. (correct answer)

Explanation: This question asks you to weaken an argument about self-checkout kiosks causing increased library circulation. To weaken this causal claim, you need to find evidence that something else might explain the 20% increase in checkouts. The argument assumes that the kiosks themselves drove the increase, rather than external factors affecting demand for library materials. The correct answer (E) provides an alternative explanation: several large courses assigned weekly readings available only as physical reserves, which would naturally increase checkouts regardless of the checkout method. This undermines the director's conclusion that kiosks caused the increase and calls into question the plan to remove more staffed desks. Choice A about extended hours is tempting but doesn't directly explain increased checkouts, while choice B about occasional failures actually supports keeping some staffed desks rather than weakening the causal claim.

Question 12

A software firm plans to improve employee productivity by switching from open-plan seating to private offices. The firm bases the plan on an internal survey in which 70% of employees reported that noise in the open-plan area makes it difficult to concentrate. The firm concludes that providing private offices will substantially increase the amount of focused work employees can do, leading to higher output. Which of the following, if true, most weakens the argument?

  1. The firm's employees collaborate frequently on projects that require short, spontaneous discussions throughout the day.
  2. Private offices would require additional construction costs and could reduce the total number of desks available in the current space.
  3. Some employees prefer to listen to music while working, regardless of the seating arrangement.
  4. In the survey, employees were not asked whether they would be willing to use noise-canceling headphones.
  5. In a pilot area where private offices were introduced, employees spent more time in scheduled meetings and less time doing individual work than they had previously. (correct answer)

Explanation: This question asks you to weaken an argument that private offices will improve productivity by reducing noise distractions. Weakening requires finding evidence that private offices might not increase focused work and output as expected. The firm assumes that because 70% of employees cite noise as a concentration problem, eliminating noise through private offices will substantially increase productivity. The correct answer (E) provides direct evidence against this assumption: in a pilot area with private offices, employees actually spent more time in meetings and less time on individual work. This suggests that private offices may paradoxically reduce the focused work time they're meant to increase, seriously undermining the productivity argument. Choice A about frequent collaboration actually supports open plans rather than weakening the private office argument, while choice B addresses costs rather than productivity effects.

Question 13

A technology firm concludes that allowing employees to work from home three days per week will increase productivity. In a three-month trial, a team that adopted the policy completed 18% more project tasks than it had in the previous three months. Because task completion is a standard measure of productivity at the firm, management infers that expanding the policy companywide will increase productivity. Which of the following, if true, most weakens the argument?

  1. During the trial, the team's projects were unusually routine and required fewer cross-team approvals than the team's typical projects. (correct answer)
  2. Some employees report that working from home reduces their commuting time.
  3. The firm's office lease expires in two years.
  4. Employees at the firm use a standardized software tool to track task completion.
  5. Many competitors offer some form of remote-work option.

Explanation: This question tests your ability to weaken an argument by identifying variables that confound its evidence. Weakening reduces support for the conclusion by suggesting alternative reasons for the observed productivity gain. The argument assumes that the remote-work policy caused the 18% increase in tasks, based on a standard measure. It overlooks differences in project complexity during the trial. Choice A weakens the argument by indicating that easier projects, not the policy, may have boosted completion rates. For example, choice B fails to weaken because commuting time savings do not contradict the causal claim. Similarly, choice C addresses lease timing unrelated to productivity evidence.

Question 14

A city's transportation office concludes that installing protected bicycle lanes on Central Avenue will significantly reduce traffic congestion there within one year. The office cites data from the past six months showing that, after a pilot lane was installed on a nearby parallel street, average car travel times during rush hour decreased by 12%. Because Central Avenue and the parallel street have similar numbers of lanes and comparable rush-hour volumes, the office infers that the same intervention will yield similar results on Central Avenue. Which of the following, if true, most weakens the argument?​​​

  1. During the six-month pilot, several large employers near the parallel street adopted permanent remote-work policies that reduced commuting by car. (correct answer)
  2. Surveys indicate that most cyclists prefer protected lanes to unprotected lanes when available.
  3. Central Avenue has a higher number of retail delivery stops per mile than most other streets in the city.
  4. The pilot lane on the parallel street cost less per mile to install than the proposed lane on Central Avenue would cost.
  5. Traffic congestion on Central Avenue is worse in winter months than in summer months.

Explanation: This question tests your ability to weaken an argument by identifying evidence that undermines its conclusion. Weakening reduces support for the conclusion by exposing flaws in the reasoning or assumptions. The argument assumes that the bike lane caused the 12% reduction in travel times on the parallel street and that similar conditions on Central Avenue will yield the same result. However, it overlooks potential alternative explanations for the observed reduction. Choice A weakens the argument by suggesting that remote-work policies, not the bike lane, may have caused the decrease in traffic. For example, choice B fails to weaken the argument because cyclists' preferences do not address whether the lane reduces car congestion. Similarly, choice C is irrelevant as it discusses delivery stops without linking to the causal inference about traffic reduction.

Question 15

A software company introduced an optional training module on its internal security policies. Employees who completed the module were involved in fewer reported security incidents than those who did not. Management concludes that requiring all employees to complete the module will substantially reduce security incidents across the company. The argument assumes that the training itself led to fewer incidents rather than differences between employees who opted in and those who did not. Which of the following, if true, most weakens the argument?​

  1. Some employees who completed the module did so because they needed it for a professional certification.
  2. The module takes less than one hour to complete and can be paused and resumed later.
  3. Employees who chose to complete the module were disproportionately in roles with limited access to sensitive systems compared with employees who did not complete it. (correct answer)
  4. The company also updated its password policy during the same year.
  5. Some security incidents are caused by external attackers rather than by employee behavior.

Explanation: This question tests your ability to weaken an argument about training effectiveness. To weaken means to provide information that undermines the logical connection between evidence and conclusion. Management assumes that the training module caused fewer security incidents among those who completed it and that mandating it will reduce incidents company-wide. The key vulnerability is assuming the training caused the difference rather than pre-existing differences between employees who chose to complete it and those who didn't. Answer C seriously weakens the argument by revealing selection bias: employees who completed the module were disproportionately in roles with limited access to sensitive systems. This suggests they were already at lower risk for security incidents due to their job roles, not because of the training, undermining the conclusion about mandatory training. Answer A, about professional certification requirements, explains some motivations but doesn't challenge the training-incident relationship.

Question 16

A school district notes that students at two middle schools that adopted a new mathematics curriculum showed larger gains on the district's standardized math test than students at other middle schools. The district superintendent concludes that adopting the new curriculum in all middle schools will raise math performance districtwide. The superintendent assumes that the curriculum, rather than differences among the schools, accounts for the gains. Which of the following casts the most doubt on the argument?​

  1. Teachers at the two adopting schools received additional professional-development workshops focused on test-taking strategies during the same year. (correct answer)
  2. Parents at several schools have expressed interest in more after-school math clubs.
  3. The new curriculum includes more group work than the previous curriculum did.
  4. The district's standardized math test is administered in the spring each year.
  5. Some students report that they prefer the visual layout of the new curriculum's textbooks.

Explanation: This question tests weakening an argument about curriculum effectiveness. To weaken means to provide evidence that the conclusion doesn't necessarily follow from the stated premises. The superintendent assumes that the new curriculum caused the test score gains and that adopting it districtwide will produce similar results. The key vulnerability is attributing gains solely to the curriculum without considering other factors. Answer A weakens the argument by revealing that teachers at the adopting schools received additional professional development on test-taking strategies during the same year. This introduces an alternative explanation—enhanced teacher training rather than the curriculum itself may have caused the gains, undermining the conclusion about curriculum adoption. Answer C, about more group work in the new curriculum, describes a feature but doesn't challenge the causal claim about test score improvements.

Question 17

A town council argues that since the installation of LED streetlights on the town's main avenue, nighttime traffic accidents on that avenue have declined. The council concludes that replacing all streetlights in the town with LEDs will reduce nighttime traffic accidents townwide. The council's reasoning relies on the assumption that the lighting change caused the decline and that other streets will respond similarly. Which of the following, if true, most weakens the argument?​

  1. The LED streetlights use less electricity than the older streetlights and therefore reduce the town's energy costs.
  2. During the same period, the town reduced the speed limit on the main avenue and added new speed-enforcement cameras there. (correct answer)
  3. Some residents have complained that the LED streetlights appear brighter than the older lights.
  4. Several accidents on side streets occur during daytime hours rather than at night.
  5. The town's main avenue has more lanes than most other streets in the town.

Explanation: This question asks you to weaken an argument about street lighting and traffic safety. Weakening requires identifying information that challenges the assumed causal relationship between evidence and conclusion. The council assumes that LED streetlights caused the decline in nighttime accidents on the main avenue and that installing LEDs elsewhere will produce similar results. The critical assumption is that the lighting change, rather than other factors, caused the accident reduction. Answer B most effectively weakens this argument by revealing that during the same period, the town reduced speed limits and added enforcement cameras on the main avenue. These traffic-calming measures provide a strong alternative explanation for the accident decline, making it unclear whether LED lights alone would reduce accidents on other streets. Answer C, about brightness complaints, addresses resident preferences but doesn't challenge the safety claims.

Question 18

A nutrition researcher reports that in a study of adults who voluntarily tracked their meals using a mobile app for eight weeks, average daily sugar intake declined by 15%. The researcher concludes that promoting the app to the general public will lead to a similar reduction in sugar consumption. The conclusion assumes that the app itself produced the reduction and that typical users will respond as the study participants did. Which of the following, if true, most weakens the argument?​

  1. Many popular meal-tracking apps include features that allow users to share progress with friends.
  2. Participants in the study were recruited from a weight-management program and were already attempting to reduce sugar intake before using the app. (correct answer)
  3. Some participants reported that scanning barcodes to log foods was more convenient than typing food names.
  4. The app's database contains nutritional information for many packaged foods sold nationally.
  5. Over the eight-week period, participants' average intake of dietary fiber increased slightly.

Explanation: This question asks you to weaken an argument about a nutrition app's effectiveness. Weakening involves finding information that challenges the reasoning or reveals alternative explanations for observed results. The researcher assumes that the app caused the 15% reduction in sugar intake and that promoting it to the general public will produce similar results. The critical assumption is that the app itself, rather than participant characteristics or motivations, drove the reduction. Answer B most effectively weakens this argument by revealing selection bias: participants were recruited from a weight-management program and were already attempting to reduce sugar intake before using the app. This means the participants were highly motivated individuals already working on dietary changes, making it unlikely that the general public would achieve similar results simply by using the app. Answer C, about barcode scanning convenience, addresses usability but doesn't challenge the causal claim about sugar reduction.

Question 19

A regional hospital notes that in the past six months, patients who used its new online appointment system had an average wait time of 9 days for a nonurgent visit, compared with 14 days for patients who scheduled by phone. The hospital administrator concludes that expanding the online system and encouraging all patients to use it will significantly reduce average wait times for nonurgent visits. The administrator assumes that the scheduling method itself is responsible for the difference in wait times. Which statement most seriously undermines the author's conclusion?​

  1. Some patients prefer phone scheduling because they can ask questions about insurance coverage during the call.
  2. The online system is unavailable in several languages commonly spoken in the region.
  3. Patients using the online system disproportionately selected providers who had recently increased their clinic hours, while phone schedulers more often booked with providers whose hours had not changed. (correct answer)
  4. The hospital's patient satisfaction scores increased slightly during the same six-month period.
  5. The online system occasionally displays an error message that requires users to refresh the page and try again.

Explanation: This question asks you to weaken an argument about reducing wait times through online scheduling. Weakening an argument involves finding information that undermines the logical connection between the evidence and the conclusion. The administrator assumes that the scheduling method itself (online vs. phone) is responsible for the shorter wait times, and that expanding online scheduling will reduce wait times for all patients. The critical assumption is that the two groups of patients are comparable except for their scheduling method. Answer C weakens this argument by revealing a confounding variable: patients using the online system disproportionately selected providers with recently increased hours, while phone schedulers booked with providers whose hours hadn't changed. This suggests that the shorter wait times may be due to increased provider availability rather than the scheduling method itself. Answer B, about language availability, might explain why some patients don't use the online system but doesn't challenge the causal claim about wait times.