We took a random sample of students to see how far UA studen…

We took a random sample of students to see how far UA students could jump before and after lunch. Before lunch, we had 8 students jump and average of 67.25 inches with a sample standard deviation of 3.65 inches. After lunch, we had 12 students jump with an average of 57.25 inches with a sample standard deviation of 9.6 inches. Construct a 90% confidence interval on the difference between the two means (assume 15 degrees of freedom).

Let  be a random sample from a population with mean  and a v…

Let  be a random sample from a population with mean  and a variance of  and let  be a random sample from a population with mean  and a variance of  and that  samples are independent of each other. Assume that sample mean values are  and  with  and . We want to test  versus . What is the value of the test statistic?