Progressive Insurance would like to test the hypothesis that a difference exists in the
proportion of students in 12th grade who text while driving when compared to the
proportion of 11th grade drivers who text. A random sample of 160 12th grade students
found that 84 texted while driving. A random sample of 175 11th grade students found
that 70 texted while driving. If Population 1 is defined as 12th grade drivers and
Population 2 is defined as 11th grade drivers, which one of the following statements is
true?
A) Because the 95% confidence interval does not include zero, Progressive Insurance
cannot conclude that a difference exists in the proportion of students in 12th grade who
text while driving when compared to the proportion of 11th grade drivers who text.
B) Because the 95% confidence interval does not include zero, Progressive Insurance
can conclude that a difference exists in the proportion of students in 12th grade who text
while driving when compared to the proportion of 11th grade drivers who text.
C) Because the 95% confidence interval includes zero, Progressive Insurance cannot
conclude that a difference exists in the proportion of students in 12th grade who text
while driving when compared to the proportion of 11th grade drivers who text.
D) Because the 95% confidence interval includes zero, Progressive Insurance can
conclude that a difference exists in the proportion of students in 12th grade who text
while driving when compared to the proportion of 11th grade drivers who text.
Sony would like to test the hypothesis that the average age of a PlayStation user is
different from the average age of an Xbox user. A random sample of 36 PlayStation
users had an average age of 34.2 years while a random sample of 30 Xbox users had an
average age of 32.7 years. Assume that the population standard deviation for the age of
PlayStation and Xbox users is 3.9 and 4.0 years, respectively. Sony would like to set α
= 0.10. The critical value for this hypothesis test would be ________.
A) 1.28
B) 1.645
C) 1.96