1. The head librarian at the Library of Congress has asked her assistant for an interval estimate of the

mean number of books checked out each day. The assistant provides the following interval estimate:

from 740 to 920 books per day. What is an efficient, unbiased point estimate of the number of books

checked out each day at the Library of Congress? (Show work/explain)

a) 740

b) 830

c) 920

d) 1,660

1. "It is desired to estimate the mean total compensation of CEOs in the Service industry. Data were

randomly collected from 18 CEOs and the 95% confidence interval was calculated to be ($2,181,260,

$5,836,180). Which of the following interpretations is correct? (Explain)

a) 95% of the sampled total compensation values fell between $2,181,260 and $5,836,180.

b) We are 95% confident that the mean of the sampled CEOs falls in the interval $2,181,260

to $5,836,180.

c) In the population of Service industry CEOs, 95% of them will have total compensations

that fall in the interval $2,181,260 to $5,836,180.

d) We are 95% confident that the mean total compensation of all CEOs in the Service

industry falls in the interval $2,181,260 to $5,836,180."

5) Suppose a department store wants to estimate the mean age of the customers of its contemporary

apparel department, correct to within 2 years, with level of confidence equal to 95%. Management

believes that the standard deviation is 8 years. The sample size they should take is ________. (show work)