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:                     

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               195                          138 

Service contracts   60                             45

The store can only sell a service contract on a new piece of equipment. Of the 195 treadmills sold, 60 purchased a service contract. Of the 138 exercise bikes, 45 purchased a service contract.

Remember to watch the instructional video and use the excel template provided to help you with the math.

Complete the following questions in the space provided below:

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

2. Interpret the meaning of the confidence interval for Treadmills at a 95% confidence level. 

3. Interpret the meaning of the confidence interval for Exercise Bikes at a 95% confidence level.

4. Are confidence intervals one-tailed or two-tailed? 

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