The university data center has two main computers. The center wants to examine whether computer 1 is receiving tasks that require processing times comparable to those of computer 2. A random sample of 12 processing times from computer 1 showed a mean of 63 seconds with a standard deviation of 18 seconds, while a random sample of 10 processing times from computer 2 (chosen independently of those for computer 1) showed a mean of 54 seconds with a standard deviation of 15 seconds. Assume that the populations of processing times are normally distributed for each of the two computers and that the variances are equal. Construct a 95% confidence interval for the difference u,-, between the mean processing time of computer 1, ,, and the mean processing time of computer 2, u. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your responses to at least two decimal places. (If necessary, consult a list of formulas.) What is the lower limit of the 95% confidence interval? What is the upper limit of the 95% confidence interval?