Repeat Problem 9 using the data of Problem 8. Problem 9 Construct the 95% confidence interval for the data of Problem 7, expressing the upper and lower limits in terms of the number of standard deviations relative to a difference of zero between ?X and ?Y. Using the data of Problem 7,interpret a confidence interval of ?in terms of d, using C .95. Does it appear that the estimate has considerable precision? Explain.