A. Cox Communications, the primary cable provider in Omaha, NE,
claims to have excellent customer service. In fact, the company
advertises that a technician will arrive approximately 25 minutes
after a service call is placed. One frustrated customer believes
this is not accurate, claiming it takes longer than 25 minutes for
a technician to arrive. The customer puts a survey on the Nextdoor
app asking other Cox customers what their experience has been. Only
11 people responded, with a mean of 27.9 minutes and standard
deviation of 3.4 minutes. Test the customer's claim with a 0.025
level of significance. (7 points)
B. For the same problem as part A, construct an appropriate
confidence interval based on the alpha level in A to support your
conclusion from part A. Recall, if you rejected the null in part A,
then your expected mean should not be included in the interval. If
you failed to reject the null hypothesis, then the hypothesized
mean should be in the interval. You should only need the
appropriate critical value and margin of error in addition to
values from part A. Correctly round your results to one decimal
place in your conclusion sentence and be sure to state that it
supports your decision to reject or fail to reject based on whether
the hypothesized value falls in the interval. (3 points)