A study is done to determine if Company A retains its workers longer than Company B.It is believed that Company A has a higher retention than Company B.

The study finds that in a sample of 11 workers at Company A their average time with the company is four years with a standard deviation of 1.5 years.A sample of 9 workers at Company B finds that the average time with the company was 3.5 years with a standard deviation of 1 year.

Test this proposition at the 1% level of significance and use df = 17