2. The Pulsar corporation sells a large sterilizer with four extendable shelves for medical tools. Company engineers believe that the time to reach operating temperature from a cold start (y, measured in minutes) is linearly related to the thickness of insulation (x, in inches). A random sample of n = 12 thicknesses was selected, and the time to reach operating temperature was recorded for each. The data and the summary statistics are given below. 1.8 0.9 2.6 1.5 2.1 3.0 2.4 2.45 2.6 8.0 7.0 6.3 6.5 6.4 5.8 8.3 6.6 6.6 where _1 2; = 23.1, >_, yi = 84.8, > niyi = 158.5, >, ; = 50.13 and )_ y? = 607.66. a. Find the estimated regression line. b. Suppose the estimated variance is 0.4439. Conduct a t test (concerning 81) for a significant regression. Use a significance level of 0.05. c. Interpret your result