A study was conducted to examine the association between lead exposure and developmental features in children. The excel file called LEAD_MAXFWT.xlsx containing the data on 99 children is located in the Data Sets folder under Contents in A2L. Children were divided into two lead exposure groups: group 1 (GROUP=1, n=64) were children who lived less than 25 km away from a lead smelter, and group 2 (GROUP=2, n=35) were children who lived more than 25 km away from a lead smelter. One important outcome measure that was captured was finger-wrist tapping scores for each hand, with the highest of the two measures representing the maximum finger-wrist tapping score (MAXFWT). Use these data to answer the questions below.

a. Conduct the appropriate test to determine if there is a significant difference in the mean maximum finger-wrist tapping scores (MAXFWT) for the two groups of children. You are not comfortable assuming that the scores are normally-distributed in the two groups of children. Assume ?=0.05. Show all calculations.

b. Obtain the p-value for the test statistic calculated in question a. Does the p-value support your conclusion from question a regarding group differences in mean MAXFWT? Show your calculations.

c. You create a box plot that compares the distribution of MAXFWT data for the two groups (see plot below), and decide that the data for both groups are approximately normally-distributed. You also test for the homogeneity of variance in the two groups, and the results suggest that the variances are approximately equal. Based on these tests, you decide to conduct a 2 sample independent t-test to determine if the mean MAXFWT differs between the two groups. Conduct this test, assuming ?=0.05. Show all calculations.

O 8 2 8 MAXFWT 8 0 0 & 2 GROUP