The following estimated regression equation was developed for a model involving two independent variables. ŷ​ =40.7+8.63x1​+2.71x^2​

After x2 was dropped from the model, the least squares method was used to obtain an estimated regression equation involving only x1 as an independent variable.

ŷ= 42.0+9.01x1
​
Required:
a. Give an interpretation of the coefficient of x1 in both models.
b. Could multicollinearity explain why the coefficient of x1 differs in the two models? If so, how?