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Hypothesis Testing Review Exercises
For each problem, perform the test, if possible.
If no data are given, set up the hypotheses and tell which
test you would use.
1.
A
Business Week
/Harris poll asked 1035 adults how well U.S. companies competed in the global
economy; 704 respondents answered good/excellent (
Business Week
, September 11, 2000).
In a
similar poll of 1004 adults in 1996, 582 respondents answered good/excellent.
Can the sample
results be used to conclude that the proportion of all adults responding good/excellent has increased
over the 4 years from 1996 to 2000?
Use
α
= .05.
2.
A national TV telethon committee is interested in determining whether donations given by males and
females differ in variability of amounts.
To test this, random samples of 25 males and 25 females
were selected from people who donated during last year’s telethon.
The following statistics were
computed from the sample data.
Use
α
= .05.
Mean
SD
Males
$12.40
$2.50
Females
$8.92
$1.34
3.
The owners of Fit and Trim, a fitness and diet club, would like to advertise that their clients lose more
than 10 pounds, on average, during their first 3 months of membership at the club.
A sample of 20
members resulted a mean weight loss of 10.1 pounds with a standard deviation of .4 pounds.
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 Fall '08
 CRISSINGER
 Statistics

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