1. A level C confidence interval is what? a. any interval with margin of error ± C b. an interval computed from sample data by a method that has probability C of producing an interval containing the true value of the parameter of interest c. an interval with margin of error ± C which is also correct C% of the time d. an interval computed from sample data by a method which guarantees that the probability the interval computed contains the parameter of interest is C 2. The upper .05 critical value of the standard normal distribution is what? a. 1.282 b. 1.645 c. 1.960 d. 2.000 3. The upper .01 critical value of the standard normal distribution is what? a. 1.645 b. 2.054 c. 2.326 d. 2.576 4. A sample of 25 seniors from a large metropolitan area school district had a mean Math SAT score of = 450. Suppose we know that the standard deviation of the population of Math SAT scores for seniors in the district is = 100. A 90% confidence interval for the mean Math SAT score µ for the population of seniors is what? (Assume the population of Math SAT scores for seniors in the district is approximately normally distributed.) a. 450 ± 32.9 b. 450 ± 39.2 c. 100 ± 1.96 d. 100 ± 176.4 5. A sample of 25 seniors from a large metropolitan area school district had a mean Math SAT score of = 450. Suppose we know that the standard deviation of the population of Math SAT scores for seniors in the district is = 100. A 90% confidence interval for the mean Math SAT score µ for the population of seniors is used. Which of the following would produce a confidence interval with a smaller margin of error? a. using a sample of 100 seniors b. using a confidence level of 95% c. using a confidence level of 99% d. using a sample of only 10 seniors Page 2 6. A sample of 25 seniors from a large metropolitan area school district had a mean Math SAT score of = 450. Suppose we know that the standard deviation of the population of Math SAT scores for seniors in the district is = 100. A 95% confidence interval for µ for the population of seniors with margin of error ± 25 is used. The smallest sample size we can take and achieve this margin of error is what? a. 25 b. 44 c. 50 d. 62 7. The probability that a fixed significance level test will reject H0 when a particular alternative value of the parameter is true is called the what? a. Type I error against that alternative b. Type II error against that alternative c. power of the test against that alternative d. the critical value of the test against that alternative 8. The mean diameter µ of a certain bolt is supposed to be 1 centimeter (cm). Diameters of bolts vary normally with standard deviation = .01 cm. When a shipment of bolts arrive, an inspector takes a SRS of 25 bolts from the shipment and measures their diameters. The inspector rejects the shipment if the sample mean diameter differs from 1 cm by more than .005 cm. Notice that the inspector is testing the hypotheses: H0: µ = 1 Ha: µ 1 What is the power of the test when µ = 1.005? a. 1 b. .9876 c. .95 d. 0.5 9. You have a SRS of size n = 9 from a normal distribution with = 1. You wish to test the hypotheses: H0: µ = 0 Ha: µ >0. You decide to reject H0 if >1. The probability of a Type I error is what? a. 0.5 b. .3174 c. .1587 d. .0013 Page 3 10. You have a SRS of size n = 9 from a normal distribution with = 1. You wish to test the hypotheses: H0: µ = 0 Ha: µ >0 You decide to reject H0 if >1. What is the probability of a Type II error when µ = 1? a. 0.5 b. .6826 c. .8413 d. .9987 11. You have a SRS of size n = 9 from a normal distribution with = 1. You wish to test the hypotheses: H0: µ = 0 Ha: µ >0 You decide to reject H0 if >1. What is the power of the test when µ = 1? a. .9987 b. 0.5 c. .1587 d. .0013 12. In a test of hypotheses, we say that the data are statistically significant at level if a. is very small b the P-value is larger than c. the P-value is smaller than d. the data indicate that an important and meaningful effect has been detected 13. In a test of hypotheses, if we insist on very strong evidence against the null hypothesis H0 we should choose to be what? a. very small b. very large c. smaller than the P-value d. larger than the P-value Page 4 ------------------------------
A particular brand of paint advertises that a one gallon can covers at least 400 square feet. A consumer group tests the claim by purchasing a sample of 4 one gallon cans and measuring the number of square feet covered by each can. The distribution of the coverage for the population of all one gallon cans of paint of this brand is normal with standard deviation 20 square feet. The number of square feet covered by the sample of cans of paint is:

410 390 380 420

14. Is this convincing evidence that the coverage is less than advertised? Using test statistic , the data is statistically significant at which of the following? a. It is not statistically significant at = .10. b. It is statistically significant at = .10 but not at = .05. c. It is statistically significant at = .05 but not at = .01. d. It is statistically significant at = .01. 15. Using the above data (#14), what are the hypotheses being tested? a. H0: µ = 400 and Ha: µ 400 b. H0: µ = 400 and Ha: µ >400 c. H0: µ = 400 and Ha: µ <400 d. H0: µ 400 and Ha: µ = 400 Page 5 ANSWER KEY 16 dec 1999 Fr. Chris Thiel AP Statistics +--------+--------+--------+--------+--------+--------+--------+ | Text | Bank | Exam | | Cat | Dif. | Text | |Chapter | Ref |Question| Answer | | Lvl. | Page | +--------+--------+--------+--------+--------+--------+--------+ | 5 2 1 B | | 5 3 2 B | | 5 4 3 C | | 5 5 4 A | | 5 6 5 A | | 5 7 6 D | | 5 70 7 C | | 5 69 8 D | | 5 64 9 D | | 5 65 10 A | | 5 66 11 B | | 5 28 12 C | | 5 29 13 A | | 5 41 14 A | | 5 42 15 C | |______________________________________________________________| Some questions may require editing due to artwork or special characters.