The Anderson = s Super Dollar had two grocery stores in Erie,
Pennsylvania. The mean time customers wait in the checkout line at the
Byrne Road store is 3.7 minute with a standard deviation of .8 minutes, for
a sample of 40 customers. The mean waiting time for the I-90 store is 3.5
minutes with a standard deviation of .7 minutes for a sample of 45
customers. At the .05 significance level can we conclude there is a
difference in the waiting time for the two stores?
The Inlet Square Shopping mall is considering two dispensing machines
for soft-drinks. Tests show that both machines control the mean amount
dispensed, however there seems to be a difference in the variability. The
Fizzit Model had a standard deviation of 0.30 ounces for a sample of 10.
The Yale Model had a standard deviation of .15 ounces for a sample of 8.
At the .05 significance level is there a difference in the variability of the
two machines?
A finance professor found the correlation between the amount of change in
her stock portfolio and the change in the Dow-Jones Industrial Average
was .43 for a sample of 15 days. At the .05 significance level, can she
conclude that there is a positive correlation between the two variables?
A production supervisor wishes to find the relationship between the
number of workers on a job and the number of units produced for a shift.
Listed below is the result for a sample of 8 days. Let the number of units
produced be the dependent variable.
Two hundred people selected at random from various levels of
management were interviewed regarding their concern for environmental
issues. The information was organized into the following table. At the .01
significance level, is it reasonable to conclude that there is a relationship
between level of management and concern regarding environmental
issues?
The Appliance Center reports on it TV commercials that Amore than 70
percent of our customers have purchased an appliance with us before. The
president of the company hired a marketing research firm to
independently validate this claim. In a sample of 200 recent buyers, 160
reported that they had, in fact, purchased and an appliance from the
Appliance Center before. At the .01 significance level is the claim of the
commercial correct?
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