Mortgage debt. Mortgage debt is the balance someone still owes on a mortgage. A monthly payable mortgage debt is dependent on factors like personal monthly income, the interest rate of a mortgage loan, personal monthly expenses, etc. The following regression equation, with an R2 of 73%, is used to predict a personal monthly payable mortgage debt

(in dollars) by considering two variables of personal monthly income (in dollars) and the interest rate (in percentage):

MortDebt = 555.6812 + 0.8258 MonInc - 56.4393 IntRate One of the following interpretations is correct. Which is it?

Explain what is wrong with the others.

a) Every 1% increase in the interest rate, the personal monthly payable mortgage debt will decrease by $56.44.

b) This model fits 73% of the points exactly.

c) For every $1 increase in personal income, the personal monthly payable mortgage debt will increase by $0.83.

d) The interest rate remaining constant, for every $1 increase in personal income, the personal monthly payable mortgage debt will increase by $0.83.