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Math 403 Exam 4
1.
The following table shows the preferences for two brands of chocolate cookie in a
recently conducted tastetest involving 245 college students.
Is the proportion of female
students who prefer cookie A significantly greater than the proportion of male students
who prefer cookie A?
Use a hypothesis test to decide, with
α
= 0.05.
Show the pvalue.
(12 points)
Cookie A
Cookie B
Total
Males
94
85
179
Females
39
27
66
Total
133
112
245
(z=.917, p=.1788, do not reject, there is not evidence to show the proportion of female
students who prefer A is greater)
2.
Mike rides his bike to work each day, and sometimes he keeps track of how long it takes.
The data for samples of rides from two different months are below.
Form a 90%
confidence interval for the difference in means for the two years, assuming the population
variances are different.
(10points)
Month
n
Mean
Standard deviation
June
12
16.78
1.32
August
14
18.79
3.24
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3.
The following dataset shows the number of disk drives a company sells during 8 years.
Year
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 Spring '08
 Barnet
 Math

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