Multiple Choice Practice for Inference for Quantitative Data: Means

Welcome to Unit 7 AP Statistics Multiple Choice Questions! Grab some paper and a pencil 📄 to record your answers as you go. You can see how you did on the Unit 7 Practice Questions Answers and Review sheet once you're done. Don't worry, we have tons of resources available if you get stumped 😕 on a question. And if solo study is not your thing, join a group in Hours! Not ready to take a quiz yet? Check out the Intro to Unit 7.

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Facts about the test: The AP Statistics exam has 40 multiple choice questions and you will be given 1 hour 30 minutes to complete the section. That means it should take you around 11 minutes to complete 5 questions.

*The following questions were not written by College Board and although they cover information outlined in the AP Statistics Course and Exam Description the formatting on the exam may be different.

1. How do you calculate the degrees of freedom for a 1 sample t test?

A. n

B. n-1

C. n/2

D. 2n

2. A matched pairs experiment would work best with a ___________ confidence interval.

A. 1 Sample T

B. 2 Sample T

C. 1 Proportion T

D. 2 Sample Z

3.  Which of the following is NOT a way to verify that our sampling distribution of our mean is approximately normal?

A. Sample plot shows no skewness or outliers.

B. Population is normally distributed

C. Sample size of at least 30

D. Sample mean of at least 30

4. A study concludes by estimating the true mean weight of giraffes in Africa by giving a 95% confidence interval of (1600, 2000). Interpret this confidence interval.

A. 95% of giraffes weigh between 1600 and 2000 pounds.

B. There is a 95% probability that a giraffe weighs between 1600 and 2000 pounds.

C. We are 95% confident that the true mean weight of giraffes is between 1600 and 2000 pounds.

D. There is only a 5% chance of selecting a giraffe that weighs outside of 1600 and 2000 pounds.

5. Which condition would allow us to use a z interval instead of a t interval to estimate a population mean?

A. When the population standard deviation is known

B. When the sample size is at least 100

C. When we know the sample mean

D. When the sample is 10% of our population

6. What happens to the width of a confidence interval as the sample size increases?

A. The width increases

B. The width decreases.

C. The width does not change with sample size.

D. Not enough information to determine.

7. Which test statistic do we always use when performing a hypothesis test for means?

A. z score

B. t score

C. chi square score

D. p-value

8. When performing a hypothesis test at the α=0.05 level, what would qualify us to reject the null hypothesis?

A. p-value<0.05

B. p-value >0.05

C. t score <0.05

D. t score>0.05

9. Which of the following represents a possible null hypothesis?

A. Ho: μ<55

B. Ho: x-bar=55

C. Ho: μ=55

D. Ho: x-bar<55

10. What part(s) of a confidence interval question determines the critical value for a one sample t interval?

A. confidence level

B. sample size

C. sample mean

D. sample size and confidence level

11. A wildlife conservationist wants to estimate the length of crocodiles in the wild. To do so, she takes a sample of 50 crocodiles and computes the following confidence interval of (14, 17) feet. What is the point estimate?

A. 21

B. 15.5

C. 17

D. 14

12. Find the t value for a 99% confidence interval of a sample size of 30.

A. 1.658

B. 2.756

C. 2.576

D. 1.96

13. After performing a hypothesis test at the α=0.1 level, I find that my alternative hypothesis is statistically significant. At which other levels would our sample be statistically significant?

A. 0.15

B. 0.05

C. 0.03

D. 0.01

14. When we fail to reject the null hypothesis and we should have rejected it, we have committed a __________.

A. Statistical Fallacy

B. Type 1 error

C. Type 3 error

D. Type 2 error

15. If I am performing a hypothesis test at the α=0.05 level, what is the probability of committing a type 1 error?

A. 0.1

B. 0.95

C. 0.05

D. 0.5

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