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 temp are shown in the following table:

month temp usage/1000

jan. 24 185.79

feb 28 214.47

mar 36 288.03

apr 42 424.84

may 56 454.58

june 54 539.03

july 68 621.55

aug 72 675.06

sept 62 562.03

oct 65 452.93

nov 46 369.95

dec 39 273.98

a) assuming that a simple linear regression model is appropriate, fit the regression model relating steam usage (y) to the average temperature (x). what is the estimate of ? 2? graph the regression line.