15.The proportion of nondefective components that the electronics manufacturer receives from these two plants is
(A) 0.982.
(B) 0.984.
(C) 0.985.
(D) 0.986.

11. A manufacturer receives parts from two suppliers. An SRS of 400 parts from supplier I finds 20 defective. An SRS of 100 parts from supplier 2 finds 10 defective. Let pt and po be the proportion of all parts from suppliers I and 2, respectively, that are defective. A 95% confidence interval for p1 - p2is (A) -.056±0.068.(B) -.056±0.054.(C) -.056±0.033.(D) .056 ±0.033.

12. In a particular game, a fair die is tossed. If the number of spots showing is either 4 or 5 you win $1； if the number of spots showing is 6 you win S4； and if the number of spots showing is 1, 2, or 3, you win nothing. Let X be the amount that you win. The expected value of X is (A) $0.00. (B) $1.00. (C) $2.50. (D) $4.00.

13.The scores of individual students on the American College Testing (ACT) Program composite college entrance examination have a normal distribution with mean 18.6 and standard deviation 6.0. At Northside High, 36 seniors take the test. If the scores at this school have the same distribution as national scores, what is the standard deviation of the sampling distribution of the average (sample mean) score for the 36 students? (A) 1.0 (B) 3.1 (C) 6.0 (D) 18.6 

14. The proportion of defective components that the electronics manufacturer receives from these two plants is(A) 0.014.(B) 0.015.(C) 0.016.(D) 0.018.

16. If a component received by the manufacturer is defective, the probabil ity that it was produced at plant A is (A) 1/7.(B) 2/7.(C) 3/7.(D) 4/7.

 17. If a component received by the manufaeturer is not defective, the probability that it was produced at plant A is (A) 0.602. (B) 0.622. (C)0.684. (D) 0.713.

18. To assess the accuracy of a laboratory scale, a standard weight that is known to weigh 1 gram is repeatedly weighed a total of n times and the mean of the weighings is computed. Suppose the scale readings are normally distributed with unknown mean and standard deviation =0.01 g. How large should : be so that a 95% confidence interval for has a margin of error of±0.0001? (A) 100(B)196(C)10000(D) 38416 

19. The probability that the researcher will commit a type I error is (A) 0.01. (B) 0.10. (C) 0.90. (D) equal to the P-value and cannot be determined until the data have been collected.

20. The probability that the researcher will commit a type II error for the particular alternative value of the parameter at which she computed the power is (A) 0.01. (B) 0.10. (C) 0.90. (D)equal to 1 -(P-value) and cannot be determined until the data have been collected.

1 國人抗原陰性發生的頻率為： (A) 0.33 % (B) 1% (C) 15 % (D) 30 %