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:
- Is there a major difference between the two pieces of equipment? Why or why not?
- Interpret the meaning of the confidence interval for Treadmills at a 95% confidence level.
- Interpret the meaning of the confidence interval for Exercise Bikes at a 95% confidence level.
- Are confidence intervals one-tailed or two-tailed?
- Construct a 95 percent confidence interval for the difference between the proportions of service contracts sold on treadmills versus exercise bikes.