For a multiple linear regression

a) Provide summary measures (at least two) of the fit of the model. Based on the summary measures, does the model provide a good fit for the data? Explain.

b) How to use the residuals against the fitted values plot to check whether the usual model conditions are met.

c) When we are doing multiple linear regression, we often discard some data. Identify those missing values and explain what they are and why they were recorded as missing.

d) Test the marginal contribution of X1, assuming that the other variables in the model

remain constant. Use a 1% significance level. So II need use H0: beta1 = 0 ?