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:
| Equipment Sales and Service Contracts Sold | ||
| 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:
- 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?


