AP Statistics Midterm Practice Problems 2
Name: ___________________________________
Yates, Moore and Starnes, The Practice of Statistics 3rd Edition, Platinum Resource Binder, W. H. Freeman and Company, New York: 2008.
CHAPTER 9: SAMPLING DISTRIBUTIONS
CHAPTER 9: SAMPLING DISTRIBUTIONS CONTINUED
CHAPTER 10: INTRODUCTION TO INFERENCE
CHAPTER 10 CONTINUED
5. The time needed for college students to complete a certain paper-and-pencil maze follows a normal
distribution with a mean of 30 seconds and a standard deviation of 3 seconds. You wish to see if the mean time
 is changed by vigorous exercise, so you have a group of nice college students exercise vigorously for 30
minutes and then complete the maze. You compute the average time X that it takes these students to complete
the maze and test the hypothesis
H o :   30, H a :   30
You find that the results are significant at the 5% level. You may also conclude
(A) That the test would also be significant at the 10% level.
(B) That the test would also be significant at the 1% level.
(C) Both of the above
(D) None of the above
6. In a test of statistical hypothesis, the P-value tells us
(A) if the null hypothesis is true
(B) if the alternative hypothesis is true
(C) the largest level of significance at with the null hypothesis can be rejected
(D) the smallest level of significance at with the null hypothesis can be rejected
7. The Survey of Study Habits and Attitudes (SSHA) is a psychological test that measures the motivation,
attitude, and study habits of college students. Scores range from 0 to 200 and follow (approximately) a normal
distribution with mean 115 and standard deviation 25. You suspect that incoming freshmen have a mean that is
different than 115, since they are often excited yet anxious about entering college. To test your suspicion, you
test the hypotheses
H o :   115, H a :   115
You give the SSHA to 25 students who are incoming freshmen and find their mean score is 116.2. The P-value of
your test is
(A) 0.1151
(B) 0.2302
(C) 0.4052
(D) 0.8104
8. Is the mean height for all adult American males between the ages 19 and 21 now over 6 feet? If the population
of all adult American males between the ages of 18 and 21 has mean height of  feet and a standard deviation of
 feet, to answer this question one would test which of the following null and alternative hypotheses?
(A) H o :   6, H a :  6
(B) H o :   6, H a : 
6
(C) H o :   6, H a :   6
(D) H o :   6, H a :   6  x
9. The heights of young American women, in inches, are normally distributed with mean  and standard
deviation  =2.4. If I want the margin of error for a 99% confidence interval to be  1inch, I should select a
simple random sample of size
(A) 2
(B) 7
(C) 16
(D) 39