• 51 questions

AP Statistics Sampling Distributions Practice Test

Unofficial practice on sampling distributions in AP Statistics: the central limit theorem, sample proportions, sample means and differences.

A researcher works out the mean of every possible sample of 25 students from one school and graphs all of those means. What is the graph?

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Unofficial practice questions, not affiliated with the College Board. Bank checked October 11, 2026.

All 51 questions

Topic 2.12: Sampling distributions and the central limit theorem 10

  • A dotplot shows the heights of 40 students chosen at random from a school. Which kind of distribution is it? College Board, AP Statistics Course and Exam Description, Unit 3 overview, "Preparing for the AP Exam"; course topic 2.12
  • A researcher works out the mean of every possible sample of 25 students from one school and graphs all of those means. What is the graph? College Board, AP Statistics Course and Exam Description, essential knowledge 2.12.A.1; course topic 2.12
  • A simulation draws samples of size 10 and another draws samples of size 100 from the same skewed population. Which histogram of sample means looks more nearly normal? College Board, AP Statistics Course and Exam Description, essential knowledge 2.12.A.4; course topic 2.12
  • A student writes that, by the central limit theorem, a big enough sample makes the data normal. What should the student have written? College Board, AP Statistics Course and Exam Description, essential knowledge 2.12.A.4; course topic 2.12
  • Household incomes in a city are skewed to the right. Random samples of 60 households are taken over and over. Which of these is approximately normal? Wikipedia, "Central limit theorem"; course topic 2.12, EK 2.12.A.4
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Topic 2.12: Sampling distributions and the central limit theorem, continued

  • In a random sample of 200 voters, 54% favor a measure. Among all voters in the city, 51% favor it. Which number is the statistic? College Board, AP Statistics Course and Exam Description, essential knowledge 1.2.A.4 and 1.2.A.5 (topic 1.2), as used in course topic 2.12
  • In an experiment with two treatment groups, a student shuffles the 40 response values between the groups 1,000 times and records the difference in group means after each shuffle. What do the 1,000 differences form? College Board, AP Statistics Course and Exam Description, essential knowledge 2.12.A.3; course topic 2.12
  • On what does the sampling distribution of a statistic depend? Wikipedia, "Sampling distribution"; course topic 2.12, EK 2.12.A.1
  • Software draws 5,000 random samples of size 50 from a population in which the proportion is 0.3 and records the sample proportion each time. What does a dotplot of the 5,000 values approximate? College Board, AP Statistics Course and Exam Description, essential knowledge 2.12.A.2; course topic 2.12
  • Two students each take a random sample of 30 from the same population, and their sample means differ. What explains this? College Board, AP Statistics Course and Exam Description, essential knowledge 1.2.A.5 (topic 1.2), as used in course topic 2.12

Topics 3.1 and 3.2: Sample proportions 14

  • A population proportion is 0.10 and the sample size is 40. Is the sampling distribution of the sample proportion approximately normal? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.B.2; course topic 3.2
  • A population proportion is 0.5. For random samples of size 100, what is the standard deviation of the sampling distribution of the sample proportion? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.A.1; course topic 3.2
  • A population proportion is 0.85. Which of these sample sizes is the smallest that meets the large-sample condition for the sample proportion? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.B.2; course topic 3.2
  • A statistic is used to estimate a parameter of 80. Over many random samples its values average 74. What does this show? College Board, AP Statistics Course and Exam Description, essential knowledge 3.1.A.1; course topic 3.1
  • A student samples 300 of a school's 2,000 students without replacement. Is the 10% condition met? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.B.1; course topic 3.2
  • For which setting is the sampling distribution of the sample proportion approximately normal? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.B.2; course topic 3.2
  • In a population, 40% of adults own a bicycle. For random samples of 150 adults, what is the mean of the sampling distribution of the sample proportion? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.A.1; course topic 3.2
  • In a random sample of 250 batteries, 15 are defective. What is the point estimate of the proportion of all such batteries that are defective? College Board, AP Statistics Course and Exam Description, essential knowledge 3.1.B.1; course topic 3.1
  • The sampling distribution of the sample proportion is centered at the population proportion p. What does this make the sample proportion? College Board, AP Statistics Course and Exam Description, essential knowledge 3.1.A.1; course topic 3.1
  • Thirty percent of a town's voters are registered as independents. For random samples of 84 voters, the standard deviation of the sample proportion is 0.05. Which interpretation is right? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.C.1; course topic 3.2
  • Twenty percent of the parts a factory makes need rework. For random samples of 400 parts, what is the standard deviation of the sampling distribution of the sample proportion? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.A.1; course topic 3.2
  • Which two conditions does the course description require when a sample is drawn without replacement? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.B.1; course topic 3.2
  • With p = 0.5 and n = 100, how many standard deviations above the mean of its sampling distribution is a sample proportion of 0.60? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.A.1; course topic 3.2
  • With p = 0.5, a researcher raises the sample size from 100 to 400. What happens to the standard deviation of the sample proportion? College Board, AP Statistics Course and Exam Description, essential knowledge 3.2.A.1; course topic 3.2

Topic 4.1: Sample means 13

  • A machine's fill volumes have a standard deviation of 9 ml. An engineer wants the mean of a sample of bottles to have a standard deviation of 1.5 ml. How many bottles go in each sample? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.A.1; course topic 4.1
  • A population has an unknown, possibly skewed shape, and a random sample of 10 is taken. What can be said about the sampling distribution of the sample mean? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.B.3; course topic 4.1
  • A population has mean 100 and standard deviation 15. For random samples of size 25, how many standard deviations above the mean of the sampling distribution is a sample mean of 106? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.A.1; course topic 4.1
  • A population has standard deviation 8. How does the standard deviation of the mean of 16 randomly chosen values compare with that of a single value? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.A.1; course topic 4.1
  • A population of incomes is extremely skewed. What does the course description say about the sample size needed for the sample mean to be approximately normal? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.B.3; course topic 4.1
  • A researcher wants to cut the standard deviation of a sample mean in half. What must happen to the sample size? Wikipedia, "Standard error"; course topic 4.1, EK 4.1.A.1
  • A sample of 120 is to be drawn without replacement. What is the smallest population size that meets the 10% condition? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.B.1; course topic 4.1
  • Commute times in a city have a standard deviation of 20 minutes. For random samples of 64 commuters, what is the standard deviation of the sample mean? Wikipedia, "Standard error"; College Board, AP Statistics Course and Exam Description, EK 4.1.A.1; course topic 4.1
  • For random samples of 36 test scores, the sample mean has mean 70 and standard deviation 2. Which interpretation of the 2 is right? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.C.1; course topic 4.1
  • Samples of size 4 and samples of size 64 are drawn from one population with standard deviation 16. How do the two sampling distributions of the sample mean compare? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.A.1; course topic 4.1
  • Test scores in a large population have mean 70 and standard deviation 12. For random samples of 36 scores, what is the mean of the sampling distribution of the sample mean? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.A.1; course topic 4.1
  • Waiting times at a clinic are skewed to the right. Random samples of 40 patients are taken. Can the sampling distribution of the sample mean be modeled as approximately normal? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.B.3; course topic 4.1
  • The weights of apples in an orchard are normally distributed. Random samples of 5 apples are weighed. What is the shape of the sampling distribution of the sample mean? College Board, AP Statistics Course and Exam Description, essential knowledge 4.1.B.2; course topic 4.1

Topic 3.9: Difference between two sample proportions 7

  • A study compares the proportion of the same 80 students who pass a quiz before a course and after it. Why does the formula for two sample proportions not apply? College Board, AP Statistics Course and Exam Description, essential knowledge 3.9.A.1 and 3.9.B.1; course topic 3.9
  • Each of two independent sample proportions has a standard deviation of 0.03. What is the standard deviation of their difference? College Board, AP Statistics Course and Exam Description, essential knowledge 3.9.A.1; course topic 3.9
  • In City 1, 60% of adults commute by car; in City 2, 45% do. Independent random samples are taken from each. What is the mean of the sampling distribution of the difference in sample proportions, City 1 minus City 2? College Board, AP Statistics Course and Exam Description, essential knowledge 3.9.A.1; course topic 3.9
  • The mean of the sampling distribution of the difference in sample proportions, School A minus School B, is -0.08. What does this say? College Board, AP Statistics Course and Exam Description, essential knowledge 3.9.C.1; course topic 3.9
  • Sample 1 has n = 40 from a population with p = 0.5. Sample 2 has n = 30 from a population with p = 0.2. Is the sampling distribution of the difference in sample proportions approximately normal? College Board, AP Statistics Course and Exam Description, essential knowledge 3.9.B.3; course topic 3.9
  • Sixty volunteers are randomly assigned to two treatments, and the proportions who improve are compared. Which condition do the data need to meet? College Board, AP Statistics Course and Exam Description, essential knowledge 3.9.B.2; course topic 3.9
  • Two populations each have proportion 0.5. Independent random samples of 50 are taken from each. What is the standard deviation of the difference in sample proportions? College Board, AP Statistics Course and Exam Description, essential knowledge 3.9.A.1; course topic 3.9

Topic 4.6: Difference between two sample means 7

  • Forty plants are randomly assigned to two fertilizers, and the mean growth of the two groups is compared. Which condition do the data need to meet? College Board, AP Statistics Course and Exam Description, essential knowledge 4.6.B.2; course topic 4.6
  • Machine A fills bottles with a mean of 20 ounces and Machine B with a mean of 25 ounces. What is the mean of the sampling distribution of the difference in sample means, A minus B? College Board, AP Statistics Course and Exam Description, essential knowledge 4.6.A.1; course topic 4.6
  • Population 1 has mean 50 and Population 2 has mean 42. For independent random samples, what is the mean of the sampling distribution of the difference in sample means, sample 1 minus sample 2? College Board, AP Statistics Course and Exam Description, essential knowledge 4.6.A.1; course topic 4.6
  • Population 1 has standard deviation 6 and Population 2 has standard deviation 4. Independent random samples of 12 and 16 are taken. What is the standard deviation of the difference in sample means? College Board, AP Statistics Course and Exam Description, essential knowledge 4.6.A.1; course topic 4.6
  • Samples of 50 are drawn without replacement from a population of 600 and from a population of 400. Is the 10% condition met? College Board, AP Statistics Course and Exam Description, essential knowledge 4.6.B.1; course topic 4.6
  • Two populations are each normally distributed. Independent random samples of 8 and 10 are taken. What is the shape of the sampling distribution of the difference in sample means? College Board, AP Statistics Course and Exam Description, essential knowledge 4.6.B.3; course topic 4.6
  • Two populations are skewed. Independent random samples of 45 and 20 are taken. Can the difference in sample means be modeled as approximately normal by the course description's rule? College Board, AP Statistics Course and Exam Description, essential knowledge 4.6.B.4; course topic 4.6

How this list was compiled: Our own questions, written to the sampling distribution topics of the College Board's AP Statistics Course and Exam Description, effective fall 2026, https://apcentral.collegeboard.org/media/pdf/ap-statistics-course-and-exam-description.pdf, read 2026-10-11: 2.12 Sampling Distributions and the Central Limit Theorem, 3.1 Estimators, 3.2 Sampling Distributions for Sample Proportions, 3.9 Sampling Distributions for the Difference Between Sample Proportions, 4.1 Sampling Distributions for Sample Means and 4.6 Sampling Distributions for the Difference Between Sample Means. Each rule was read on 2026-10-11 in the essential knowledge statement or the Wikipedia article named under its question, and every worked answer was recomputed. Licence: Own work. Short quotations from the public documents named under each question.

How it works

This AP Statistics sampling distributions practice test has 51 questions of our own on the central limit theorem and on the sampling distributions of proportions, means and their differences. It is unofficial and not affiliated with the College Board.

Read the full guide

Where sampling distributions sit now

The College Board revised AP Statistics for the 2026-27 school year. Its course description, effective fall 2026 and read October 11, 2026, has five units and none named Sampling Distributions. The bank follows the topics that hold the material: 2.12 (10 questions), 3.1 and 3.2 on sample proportions (14), 4.1 on sample means (13), and 3.9 and 4.6 on differences (14). The description gives topics no weights, so the spread is ours.

How the answers are checked

Each rule is cited to an essential knowledge statement of the course description or to a Wikipedia article, and every worked answer was recomputed from the numbers in its question.

  • Say which distribution you mean: the population, the data in one sample, or a statistic over repeated samples.
  • For proportions, check np and n(1 - p) are both at least 10. For means from a non-normal population, check n is at least 30.
  • Four times the sample size halves the standard deviation of a sample mean or a sample proportion.

Questions and answers

What unit is sampling distributions in AP Statistics?

In the older framework of nine units it was the fifth, Sampling Distributions. The description effective fall 2026 has five units and spreads the material over Unit 2 (topic 2.12), Unit 3 (3.1, 3.2, 3.9) and Unit 4 (4.1, 4.6).

What does an AP Stat sampling distribution practice test cover?

Simulating a sampling distribution, the central limit theorem, unbiased estimators, and the mean, the standard deviation and the conditions for a normal model for a sample proportion, a sample mean and the difference of two of each.

What is a sampling distribution?

The distribution of the values a statistic takes over all possible samples of one size from one population. It is not the population, and it is not the data in a single sample.

When is a sampling distribution approximately normal?

For a sample proportion, when np and n(1 - p) are both at least 10. For a sample mean, when the population is normal or n is at least 30; an extremely skewed population may need a much larger sample.

Are these real AP Statistics exam questions?

No. The College Board owns the real questions, and none appears here, even in other words. Every question was written for this page from the topics the course description lists.