The summary statistics given in Table 7.37 were computed from the data in the Birth Weight data set for the weights of babies for white mothers by mother’s smoking status. Use the summary statistics in Table 7.37 to answer the following:

(a) Based on the observed samples, is it reasonable to assume ????N ≈ ????Y? Explain.

(b) Compute the estimated standard error of ̄????− ̄????.

(c) Assuming that each population sampled is approximately normally distributed, test ????0 ∶ ????N ≤ ????Y at the ???? = 0.01 level.

(d) Compute the approximate ????-value for the test in part (c).

(e) Compute a 95% confidence interval for the difference in mean birth weight of a baby born to a white mother according to smoking status (i.e., ????N − ????Y).