Y = β0 + β1X + β2X2 + β3X3 + ε
where X = number of widgets produced during the week and Y = total production cost for the week. For 15 weeks of data, we found that SSR = 215,475 and SST = 229,228. For this model, we obtain the following estimated regression equation (t-statistics for each coefficient are in parentheses):
a For α = 0.10, test H0: βi = 0 against Ha: βi ≠ 0 (i = 1, 2, 3).
b Determine R2 for this model. How can the high R2 value be reconciled with the answer to part (a)?