Suppose the number of equipment sales and service contracts that a

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Suppose the   number of equipment sales and service contracts that a store sold during the   last six (6) months for treadmills and exercise bikes was as follows:

     

                          Treadmill          Exercise Bike

     

Total sold                         185                               123

     

Service contracts         67                                 55

     

The store can   only sell a service contract on a new piece of equipment. Of the 185   treadmills sold, 67 included a service contract and 118 did not.

     

Complete the   following questions in the space provided below:

     

1. Construct a 95   percent confidence interval for the difference between the proportions of   service contracts sold on treadmills versus exercise bikes.

 

2. Is there a   major difference between the two pieces of equipment? Why or why not?