We would like to estimate the value of the mean of some population. Ten statisticians each take separate random samples of 100 individuals from the population and each of them calculates a 90% confidence interval. What is the probability that exactly eight of their confidence intervals will contain the value of /4?
0.1445
(B) 0.1937
(C) 0.2324
(D) 0.2891
depends on the value of /
17. We would like to construct a confidence interval to estimate the true mean systolic blood pressure of all healthy adults to within 10 Hg (millimeters of mercury). We have a sample of 25 adults available. Systolic blood pressures of healthy adults are known to follow a normal distribution with a standard deviation of 8.0 Hg. What is the maximum confidence level that can be attained for our interval?
(A) 80%
(B) 90%
(C) 95%
(D) 99%
(E) 98%
Lumber intended for building houses and other structures must be monitored for strength. A random sample of 25 specimens of Southern Pine is selected, and the mean strength is calculated to be 3700 pounds per square inch. Strengths are known to follow a normal distribution with a standard deviation of 500 pounds per square inch. An 85% confidence interval for the true mean strength of Southern Pine is:
(A) (3615, 3785)
(B) (3671, 3729)
(C) (3556, 3844)
(D) (3544, 3856)
(E) (3596, 3804)
We would like to estimate the true mean weight of all pickerel in a large lake. Weights of pickerel in the lake are known to follow a normal distribution with a standard deviation of 0.27 kilograms. What sample size is required to estimate the true mean to within 0.08 kilograms with 99.7% confidence?
(A) 68
(B) 72
(C) 70
(D) 74