ON SPSS

The birth weight of an infant has been hypothesized to be associated with the smoking status of the mother during the first trimester of pregnancy. Following is the information on the birth weights of the infants according to the smoking status of the mother. Mother's smoking status is divided into four groups: Group I - Non smoker, Group II - Ex-smoker, Group III - Current smoker and smoke less than one pack per day, Group IV - Current smoker and smoke greater than or equal to one pack per day. The data is stored in SPSS file Ex4a.sav

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Birth weights in pounds

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Group I Group II Group III Group IV

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7.5 5.8 5.9 6.3

6.2 7.3 6.2 6.8

6.9 8.2 5.8 5.7

7.4 7.1 4.9 4.7

9.2 7.8 8.3 ` 6.2

8.3 7.9 7.2 5.8

7.6 7.2 6.2 5.4

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Do the data indicate at 1% level of significance, that the average birth weights differ over all in the four groups? Assume normal distribution for the birth weights of the infants. Test for the differences between means of each pair of groups and summarize your results. Briefly describe what your multiple comparison tests do.