For the models E(y) = + x and E(y) = + 1x1 + 2x2, express

For the models E(y) = α + βx and E(y) =

α + β1x1 + β2x2, express null hypotheses in terms of correlations that are equivalent to the following:

(a) H0: β = 0.

(b) H0: β1 = β2 = 0.