Consider a model of the influence of the average number of cigarettes the mother smoked per day during pregnancy on infant birth weight. The following simple regression model was estimated with data on n = 1388 births:
weight = 119.77-0.514×cigarettes (17.2) (0.25)
where the standard errors of the estimates are in the parathesis.
a) Test whether the slope is 0.
b) Calculate the p-value for the estimate of slope.
c) Construct a 95% confidence interval for the slope.