Sampling Distribution and Confidence Intervals

7.11 A simple random sampleof n = 300 full-time
employees is selected from a company list containing the
names of all, N = 5,000 full-time employees in order to
evaluate job satisfaction.
a. Give an example of possible coverage error.
b. Give an example of possible nonresponse error.
c. Give an example of possible samplingerror.
d. Give an example of possible measurement error.

7.15 Given a normal distributionwith m = 100 and
s = 10, if you select a sample of n = 25, what is the probabilitythat
X is.
a. less than 95?
b. between 95 and 97.5?
c. above 102.2?
d. There is a 65% chance that X is above what value?

7.21 Time spent using e-mail per session is normally distributed,
with m = 8, minutes and s = 2 minutes, if you
select a random sample of 25 sessions,
a. what is the probability that the sample meanis between
7.8 and 8.2 minutes?
c. If you select a random sample of 100 sessions, what is
the probability that the sample mean is between 7.8 and
8.2 minutes?

The expert examines sampling distributions and confidence intervals.