Suppose the number of equipment sales and service contracts that a store sold during the last six months for treadmills and exercise bikes was as follows: 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: Construct a 95 percent confidence interval for the difference between the proportions of service contracts sold on treadmills versus exercise bikes. Is there a major difference between the two pieces of equipment? Why or why not?