Practice Test 73 - AP Statistics

20 questions. Answer them in any order, then submit to see your score and every explanation.

A restaurant measured the wait time (in minutes) for 70 customers on a Saturday. The summary statistics were: mean $= 24.8$ min, median $= 21.0$ min, standard deviation $= 12.5$ min, five-number summary $(5, 14, 21, 30, 78)$ , and IQR $= 16$ min. Which interpretation is correct?
A school nurse measures the heights (in inches) of 52 ninth-grade students. The histogram is described as having two distinct peaks: one around 61–63 inches and another around 67–69 inches, with a noticeable dip in frequency around 64–66 inches. Which statement best describes the distribution?
A movie theater manager wants a point estimate of the population proportion $p$ of all customers who buy popcorn. Over one weekend, the manager records whether each customer in the first 300 tickets sold on Saturday purchased popcorn, computes the sample proportion $\hat p$ , and reports $\hat p$ as the point estimate for $p$ for all customers over the entire weekend. Which statement describes whether the estimate is biased?
A company recorded whether employees work remotely (Yes/No) and whether they report being satisfied with work-life balance (Satisfied/Not). The purpose is to compare the satisfaction rates between remote and non-remote employees using conditional proportions. Which comparison is supported by the data? Counts: Remote: Satisfied 84, Not 36 (Total 120). Not remote: Satisfied 150, Not 50 (Total 200).
A principal wants to compare the average time it takes students to finish a standardized reading test when taken on paper versus on a computer. She randomly assigns 120 students to take the paper version and 120 students to take the computer version. The paper group's mean time is 54 minutes; the computer group's mean time is 49 minutes. Which conclusion is supported by the data?
A fair six-sided die is rolled once. Let Event A be "the result is even" and Event B be "the result is greater than 4." Which statement about Events A and B is correct?
A bookstore tracked the number of books purchased per transaction for 52 customers on a Saturday, counting the total items on each receipt. The dotplot shows the distribution. Which feature of the distribution is most evident?
A city compares mean wait times (minutes) at two DMV locations. An independent random sample of $n_1=12$ customers from Location 1 and $n_2=12$ customers from Location 2 is selected, and $\bar{x}_1-\bar{x}_2$ is computed. Which statement is correct about using a normal model for the sampling distribution of $\bar{x}_1-\bar{x}_2$ ?
A chemistry teacher wants to test whether three different lab instruction formats (video demo, written instructions, and live teacher demo) affect lab report scores. There are 3 lab sections meeting on different days (Monday, Wednesday, Friday), and the teacher suspects day-of-week differences (fatigue, scheduling) could affect scores. Each section must use only one format to avoid confusion during the lab. Which experimental design is most appropriate?
A nutritionist compares mean sodium intake (mg/day) for adults following Diet A versus Diet B. Using independent random samples, a 90% confidence interval for the difference in population means was found to be $(\mu_A-\mu_B)\in(120,\,340)$ . Which interpretation is correct?
A school counselor wants to study whether the amount of time students spend on social media is associated with sleep. For each student in a random sample of 80 juniors, the counselor records daily social media time (in minutes) and hours of sleep last night. The research goal is to use social media time to help predict sleep. Observational units are the individual juniors. Which classification is correct for the two variables?
In a region, daily high temperatures in April are approximately Normal for the population of April days, with mean $\mu=70^\circ\!F$ and standard deviation $\sigma=5^\circ\!F$ . A forecasted high of 80 $^\circ\!F$ is noted. Which statement about the marked value is correct?
A psychologist compares mean reaction time (ms) for participants after drinking caffeine vs drinking no caffeine. From two independent random samples, a 92% confidence interval for $(\mu_{caff}-\mu_{no\ caff})$ is $(-25, -5)$ . Which interpretation is correct?
An auto manufacturer compares average stopping distance (in feet) for cars equipped with new brake pads versus standard brake pads, and wants to know if the new pads result in a different mean stopping distance. A random sample of 25 cars with new pads had a mean stopping distance of 128 feet, and a random sample of 27 cars with standard pads had a mean of 133 feet. Let $\mu_{new}$ and $\mu_{std}$ be the true mean stopping distances for the two pad types. Which hypotheses are appropriate?
A streaming service wants to estimate the proportion of all its subscribers who are satisfied with a new interface. The company emails a survey link to every subscriber and analyzes the first 10,000 responses received within 24 hours. No random selection is used among respondents. Which statement best describes the sample representativeness?
A grocery chain wants to estimate the mean amount (in dollars) customers spend per visit. Two different analysts each take an independent simple random sample of 60 receipts from the same month. Analyst 1 finds a mean of $42.10; Analyst 2 finds a mean of $45.80. Why might the sample results differ?
A wildlife biologist claims that between 30% and 40% of a certain bird species in a region carry a particular parasite. A random sample of 250 birds is tested, and a 95% confidence interval for the true proportion carrying the parasite is $(0.33, 0.39)$ . Is the claim supported by the confidence interval?
A researcher surveys a single random sample of 300 adults and records two categorical variables for each person: exercise level (Low, Moderate, High) and sleep quality (Poor, Fair, Good). The two-way table summarizes the counts. Which test is appropriate, and what are the correct hypotheses?
A study is conducted to explore the relationship between two variables. For each of 100 participants, their daily screen time (in hours) and their score on a happiness scale (from 1 to 10) are recorded. How is this data best classified?
Which of the following statements provides the best definition of a discrete random variable?

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