ST 101
Practice Problems Exam 1
page 2
8.
Twenty-seven applicants interested in working for the Food Stamp program took an examination designed to
measure their aptitude for social work.
The following test scores were obtained:
79, 93, 84, 86, 77, 63, 46, 97, 87, 88, 87, 92, 68, 72, 86, 98, 81, 70, 66, 98, 59, 76, 68, 91, 94, 85, 88.
a.
Find
.
U
"
b.
Construct a boxplot for these observations.
Do you observe any outliers?
9.
A manufacturer of television sets has found that for the sets he produces, the lengths of time until the first
repair can be described by a normal distribution with a mean of 4.5 years and a standard deviation of 1.5
years. If the manufacturer sets the warrantee so that only 10.2% of the 1st repairs are covered by the
warrantee, how long should the warrantee last?
10. Suppose the amount of tar in cigarettes is described by a normal model with a mean of 3.5 mg and a standard
deviation of 0.5 mg.
a. What proportion of cigarettes have a tar content that exceeds 4.25 mg?