Homework 4 (22 points)
STAT 210
Name(s) ______SOLUTION______
Due: Tuesday, October 9th by 4pm
1. Cell phones have become a very prominent part of our society in the last few years. Some
individuals use a cell phone as their primary means of communication. With this in mind,
several laws have been created to reduce the number of accidents on the road which can be
attributed to cell phone usage. One of the questions on the student data survey asked whether
the individual texts while driving. Of the 121 males sampled, 103 said they text while driving.
Of the 208 females sampled, 171 said they text while driving.
Research Question – Does the data provide evidence there is a difference in the
proportion of males and females that text while driving?
a. Determine the null and alternative hypotheses that would be used to test the research
question. You may write these in words or symbols. (3 points)
H0: pmales = pfemales
Ha: pmales ≠ pfemales
b. Using JMP, carry out the analysis and identify the appropriate test statistic and p-value.
i. If no test statistic is required, then simply write no test statistic.
ii. If a test statistic is required, then calculate the expected counts that would be
used in the computation of the test statistic.
Paste or provide a detailed sketch of your JMP output below. (4 points)
Male
Female
Total
Text While Driving
103
171
274
Don’t Text While Driving
18
37
55
Total
121
208
329
Expected Counts:
Male/Text  121*(274/329) = 100.77
Male/No Text  121*(55/329) = 20.22
Female/Text  208*(274/329) = 173.22
Female/No Text  208*(55/329) = 34.77
Test Statistic = 0.466
p-vale = 0.4948
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c. Using your p-value from part b, does this study provide evidence for the research
question? Explain. (4 points)
No evidence (p-value = 0.4948) that there is a difference in the proportion of
males and females who text while driving.
2. Two questions on the student data survey asked if an individual drinks alcohol and if an
individual has a tattoo. The data is summarized below.
Drink Alcohol
Doesn’t Drink Alcohol
Total
Tattoo
66
18
84
No Tattoo
149
96
245
Total
215
114
329
Research Question – Are individuals who drink alcohol more likely to get a tattoo than
those who don’t drink alcohol?
a. Determine the null and alternative hypotheses that would be used to test the research
question. You may write these in words or symbols. (3 points)
H0: palcohol ≤ pno alcohol
Ha: palcohol > pno alcohol
b. Using JMP, carry out the analysis and identify the appropriate test statistic and p-value.
i. If no test statistic is required, then simply write no test statistic.
ii. If a test statistic is required, then calculate the expected counts that would be
used in the computation of the test statistic.
Paste or provide a detailed sketch of your JMP output below. (4 points)
No Test Statistic
p-vale = 0.0.0020
c. Using your p-value from part b, does this study provide evidence for the research
question? Explain. (4 points)
Evidence (p-value = 0.0020) that individuals who drink are more likely to get a
tattoo than those who don’t drink alcohol.
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