A multiple regression model has the form: As x2 increases by 1 unit, holding constant x1, then the value of y will increase by: ^ is over y = 5.25 + 2.5x1 + 4x^2

A) 2.5 units
B) 7.75 unit
C) 4 units on average
D) 11.75 units on average

To determine how the value of y changes as x2 increases by 1 unit, we need to look at the coefficient of x2 in the regression model. In this case, the coefficient of x2 is 4.

This means that for every 1 unit increase in x2, while holding x1 constant, the value of y is expected to increase by 4 units.

Therefore, the correct answer is option C) 4 units on average.

To determine how the value of y will change as x2 increases by 1 unit, we need to examine the coefficient associated with x2 in the multiple regression model.

In the given multiple regression model: y = 5.25 + 2.5x1 + 4x^2

The coefficient associated with x2 is 4.

Therefore, as x2 increases by 1 unit, the value of y will increase by 4 units.

Thus, the correct answer is C) 4 units on average.