D. Find the values of the t-distribution that bound the middle a. 0.80 of the area under the curve for the distribution v=18 b. 0.99 of the area under the curve for the distribution with v=15 E. A...

Extracted text: D. Find the values of the t-distribution that bound the middle a. 0.80 of the area under the curve for the distribution v=18 b. 0.99 of the area under the curve for the distribution with v=15 E. A manufacturing firm claims that the batteries used in their electronic games will last an average of 25 hours. To maintain tis average, 15 batteries are tested each month. The computed t- value falls between - to.005 and to.005, the firm is satisfied with its claim. What conclusion should the firm fraw froma sample that has a mean of 23.5 hours and standard deviation s= 3 hours? Assume the distribution of battery lives to be approximately normal.