1. A small study (n=10) is designed to assess whether there is an association between smoking in pregnancy and low birth weight. Low-birth-weight babies are those born weighing <5.5 pounds. The following data represent the birth weights, in pounds, of babies born to mothers who reported smoking in pregnancy and to those who did not.

Mother smoked during pregnancy	5.0	4.2	4.8	3.3	3.9
Mother did not smoke during pregnancy	5.1	4.9	5.3	5.4	4.6

(b) The following data represent the number of playground injuries occurring among children aged 5-9 years over a 3-month period in 12 playgrounds in and around the neighborhoods of Boston. Playground injuries include fractures, internal injuries, lacerations, and dislocations. The question of interest is whether there are differences in the numbers of injuries at playgrounds in various locations. The data below represent the numbers of injuries recorded at four randomly selected playgrounds located on school properties, at day-care centers, and in residential neighborhoods. Run the appropriate test at a 5% level of significance.

School properties	39	51	42	29
Day care centers	28	25	30	15
Residential neighborhoods	18	16	25	22