STAT 121 - Credit Quiz 29 – with verified
solutions graded A+
The following situation applies to questions 1-4:
The department of motor vehicles wants to check whether drivers have a slower reaction time
after drinking two cans of beer. This was done by selecting a sample of 19 drivers and randomly
assigning them to one of the two groups. The reaction times (measure in seconds) in an
obstacle course are measured for a group of 10 drivers who had no beer. The other group of 9
drivers were given two cans of beet each and their reaction times on the same obstacle course
are measured.
What are the correct null and alternative hypotheses for this test? Use "N" for no beer and "B"
for two cans of beer. - correct answer ✔✔H0: µN = µB vs. Ha: µN < µB
What is the parameter of interest? - correct answer ✔✔The difference between the mean
reaction time of all those who drink no beers and the mean reaction time of all those who drink
two cans of beer
Plots of the data are shown below:
Is the normality condition met for this test? - correct answer ✔✔Yes, since both histograms
have no outliers.
Suppose the conditions were all met and the test statistic is t = 2.560. What is the associated p-
value? - correct answer ✔✔0.01 < p-value < 0.02
The following scenario applies to questions 5-6:
solutions graded A+
The following situation applies to questions 1-4:
The department of motor vehicles wants to check whether drivers have a slower reaction time
after drinking two cans of beer. This was done by selecting a sample of 19 drivers and randomly
assigning them to one of the two groups. The reaction times (measure in seconds) in an
obstacle course are measured for a group of 10 drivers who had no beer. The other group of 9
drivers were given two cans of beet each and their reaction times on the same obstacle course
are measured.
What are the correct null and alternative hypotheses for this test? Use "N" for no beer and "B"
for two cans of beer. - correct answer ✔✔H0: µN = µB vs. Ha: µN < µB
What is the parameter of interest? - correct answer ✔✔The difference between the mean
reaction time of all those who drink no beers and the mean reaction time of all those who drink
two cans of beer
Plots of the data are shown below:
Is the normality condition met for this test? - correct answer ✔✔Yes, since both histograms
have no outliers.
Suppose the conditions were all met and the test statistic is t = 2.560. What is the associated p-
value? - correct answer ✔✔0.01 < p-value < 0.02
The following scenario applies to questions 5-6:
