13.75 Multiple Choice: Interpret parameter If yn = 2.4 + 4x1 + 3x2 - 6x3, then controlling for x2 and x3, the change in the estimated mean of y when x1 is increased from 25 to 50

a. equals 100.

b. equals 0.10.

c. Cannot be given—depends on specific values of x2 and x3.

d. Must be the same as when we ignore x2 and x3.