The following model was fitted to a sample of 60 families in order to explain household milk consumption: yi = a+ BiXu+ BzXzi+ u where yi= milk consumption, in litres per week X1/ = weekly family income, in hundreds of dollars X2 = family size. Part of the estimation results are as follows: Observations 60 Sum of Squared Residual 88.2 Total Sum of Square 162.1 Coefficients Standard Error Intercept -0.025 0.0 X1 0.052 0.023 X2 1.14 0.35 c) Test whether family size can significantly explain the household milk consumption at the 1% level. Specify all relevant steps of the hypothesis testing procedure