Test hypotheses about single coefficients and about linear combinations of coefficients in a multiple regression model. In particular,

a. What is the difference between a one-tail and a two-tail test?

b. How do you compute the \(p\)-value for a one-tail test, and for a two-tail test?

c. What is meant by "testing the significance of a coefficient'?

d. What is the meaning of the \(t\)-values and \(p\)-values that appear in your computer output?

e. How do you compute the standard error of a linear combination of coefficient estimates?