Smoking and birth weight, post hoc comparisons. The ANOVA in Exercises 13.3 found that birth weight of four groups of infants differed significantly according to the smoking status of mothers (P

= 0.042). Table 13.3 lists the data for the analysis. Data are also available online in the file SMOK_BW.SAV.

(a) Conduct post hoc comparisons using the LSD method.

Summarize these results in concise narrative form.

(b) Incorporate Bonferroni’s correction into each of the P-value calculated in part (a).

(c) Calculate 95% confidence intervals for all possible mean differences incorporating Bonferroni adjustments.