11.77 Based on a sample of 45 observations, the population regression model yi = b0 + b1xi + ei was estimated. The least squares estimates obtained were as follows:

b0 = 60 and b1 = 15 The regression and error sums of squares were as follows:

SSR = 254 and SSE = 103

a. Find and interpret the coefficient of determination.

b. Test at the 5% significance level against a two-sided alternative the null hypothesis that b1 is 0.

c. Find a

45 i=1 1xi - x22