Q4. The number of pounds of steam used per month by a chemical plant is thought to be related to the average ambient temperature (in F) for that month. The past year's usage and temperature are shown in the following table: Month Temp. Usage/1000 Month Temp. Usage/1000 Jan. 21 185.79 Jul. 68 621.55 Feb. 24 214.47 Aug. 74 675.06 Mar. 32 288.03 Sept. 62 562.03 Apr. 47 424.84 Oct. 50 452,93 May. 50 454.58 Nov. 41 369.95 June 59 539.03 Dec. 30 273.98 (a) Assuming that a simple linear regression model is appropriate, fit the regression model relating steam usage (y) to the average temperature (x). (b) What is the estimate of expected steam usage when the average temperature is 55F?