(a) If the number of measurements are greater than the total number of parameter, what effect would it have on 𝑋

[answerhappygod]

(a) If the number of measurements are
greater than the total number of
parameter, what effect would it have
on 𝑋T𝑋 and how would it be
translated in a practical case?
(b) If OLS for alpha in a Multiple Regression Model is given by
alpha_hat = (𝑋T𝑋)-1
XTY and 𝑋T𝑋 is not
invertible, what would be most true about
alpha_hat?