Hyp t test 2 samp 4

The director of training for an equipment manufacturing company is interested in determining whether different training methods have an affect on the productivity of assembly line employees. She randomly assigns 42 newly hired employees into two groups of 21. The first group receives an on-line training program and the second receives a team based training program. At the end of the training, the employees are evaluated on the time (in seconds) that it takes to assemble a part. The results follow. A 95% confidence interval estimate of the difference in the mean assembly times. What is the upper limit of the interval?

On-Line

19.4 16.7 20.7 19.3 21.8 16.8 14.1 17.7 16.1 19.8 16.8

19.3 14.7 16.0 16.5 17.7 16.2 17.4 16.4 16.8 18.5

Team

22.4 13.8 18.7 18.0 19.3 20.8 15.6 17.1 18.0 28.2 21.7

20.8 30.7 24.7 23.7 17.4 23.2 20.1 12.3 15.2 16.0

A. 2.33 min

B. 2.19 min

C.4.12 min

D. None of these