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Hourly Temp. Weekly fuel consump. Week (F) 28.0 28.0 32.5 39.0 45.9 57.8 58.1 62

ID: 3316706 • Letter: H

Question

Hourly Temp. Weekly fuel consump. Week (F) 28.0 28.0 32.5 39.0 45.9 57.8 58.1 62.5 i (MMcf) 13.4 13.8 12.4 10.8 9.4 9.5 8.0 7.5 2 784.00 784.00 1056.25 1521.00 2106.81 3340.84 347.2 2 347.2 347.2 4 347.2 347.2 347.2 3375.61 347.2 347.2 7 3906.25 (a) Calculate SS, and SS (b) Compute the least squares point estimates of the regression parameters and (c) Suppose a weather forecasting service predicts that the average hourly temperature in the next week will be 40°F, can you predict the corresponding amount of fuel (in millions of cubic feet-MMcf-of natural gas) consumption according to your (linear) regression model?

Explanation / Answer

a) SS_xx = 16874.76 - (351.8)^2 / 8 = 1404.355

SS_xy = 3480.31 - 351.8 * 84.8 /8

= -248.77

b)

b1 = Sxy/Sxx = -248.77/1404.355 = -0.177141

b0 = ybar - b1 * xbar

= 84.80/8 + 0.177141* 351.8/8

=18.389775

c)

x =40

y = b0 + b1 *x

=  18.389775    -0.177141 * 40

= 11.304135