A packaging company obtained data on the size (X1) of a lot and the cost (Y ) of assembling the lot. A scatterplot of the data suggested a broken straight line regression with a breakpoint at lot size 250. The following linear model was formulated: Y = B0 + B1X1 + B2X2 + B3X3 + e where X2 = 1 or 0 depending on whether the lot size was >= 250 or < 250 and where X3 = X1X2.
Which one of the following hypotheses is equivalent to the statement: ?The two regression lines have the same intercept term.??
(a) H0 : B0 = 0 (b) H0 : B1 = 0 (c) H0 : B2 = 0 (d) H0 : B3 = 0.
Substantiate your answer by exhibiting appropriate algebraic manipulations.