Question 1
Jiffy Lube, a company that specializes in quick oil changes, claims that the average time it takes them to change
the oil is less than 30 minutes. You collect a sample of the amount of time it took for 25 randomly chosen oil
changes and found that the mean oil change time is 28 minutes. If the standard deviation of the population is 5
minutes, what would be the p-value if you want to see if you can prove Jiffy Lube’s claim?
.977
.046
.023
< .001
Question 2
Acme home repairs claims it takes them on average four hours or less to fix a home air conditioning units. Based
on your experience, you think that is laughable. You collect data from 40 randomly chosen home repairs. The
average of your sample is 3.7 hours. The population standard deviation of repairs times is one hour. What is the
p-value for a test of hypothesis where you try to prove that the repairs take longer than four hours on average?
.9711
.0289
.058
0
Question 3
The Department of Transportation is considering whether or not to buy truck scales from ACME. They are
concerned that the scales are biased either high or low. They weighed a truck that they knew weighed five
metric tons on forty of ACME’s scales. The average weight of the truck using these scales was found to be 4.95
metric tons. The population standard deviation of the truck weight is .2 metric tons. If you want to prove that
the average weight of the truck according to these scales is not five metric tons, what would be the p-value?
.050
.057
.9431
.114
Question 4
Research has been conducted to determine how many tweets the average undergraduate sends during the
average 75 minute class. Based on the following printout, what can you conclude given a level of significance of
.10.
Students tweet less than 60 times per class.
The students tweet more than 60 times per class
The students average 60 tweets per class.
the test is inconclusive
Question 5
Research has been conducted to determine how many tweets the average undergraduate sends during the
average 75 minute class. Based on the following printout, what can you conclude at the .02 level of significance.
Students tweet less than 60 times per class.
The students tweet more than 60 times per class
The students average 60 tweets per class.
the test is inconclusive
Question 6
Research has been conducted to determine how many tweets the average undergraduate sends during the
average 75 minute class. Based on the following printout, what can you conclude at the .06 level of significance.
Students tweet less than 60 times per class.
The students tweet more than 60 times per class
The students average 60 tweets per class.
the test is inconclusive
Question 7
The Treasury is conducting a study to determine the percentage of taxpayers that file online. They want to prove
that more than 60% of taxpayers file online. Based on the printout below, what can you conclude at the .02 level
of significance?
more that 60% of taxpayers file online
less than 60 percent of taxpayers file online
60 percent of taxpayers file online
the test is inconclusive
Question 8
It has been claimed that less than 30% of men are fans of the Twilight series movies. On the basis of the printout
below, what can you say about this claim at the .06 level of significance?
less than 30% of men like the Twilight series movies.
more than 30% of men like the Twilight series movies.
30% of men like the Twilight series movies.
the results are inconclusive
