For males the expected pulse rate is 70 per second and the standard deviation is 10 per second. For women the expected pulse rat
e is 77 per second and the standard deviation is 12 per second. Let !X ¼ the sample average pulse rate for a random sample of 40 men and let !Y ¼ the sample average pulse rate for a random sample of 36 women.What is the approximate distribution of \overline{X}-\overline{Y} ? Justify your answer.