7. Data Set 7 "IQ and Lead" in Appendix B lists full IQ scores for a random sample of subjects with low lead levels in their blood and another random sample of subjects with high lead levels in their blood. Round to one decimal place for your calculations. (10 pts.)

low blood lead level= n= 78, xbar = 92.9, s=15.3

high blood lead level = n= 21, xbar = 89.9, s= 9

Create a 95% confidence interval estimate on the difference between the Low and High blood lead levels. Assume blood lead levels are normally distributed and 2 2. (6 pts.)

C.I. = (__________, __________)

From the CI in part A, can it be concluded that there is a significant difference between the Low

and High blood lead levels? How did you make this determination? (2 pts.)

Calculate the pooled standard deviation for this data. (2 pts.)