Question

# The birth weights for two groups of babies were compared in a study. In one group...

The birth weights for two groups of babies were compared in a study. In one group the mothers took zinc supplement during pregnancy. In another group, the mothers took a placebo. A sample of 126 babies in the zinc group had a mean birth weight of 3305 grams. A sample of 113 babies in the placebo group had a mean birth weight of 3476 grams. Assume that the population standard deviation for the zinc group is 871 grams, while the population standard deviation fuller the placebo group is 672 grams. determine the 90% confidence interval for the true difference between the mean birth weights for zinc babies versus the placebo babies
1) find the point estimate for the true difference between the population means

2) calculate the margin of error of a confidence interval for the difference between the two population means.round your answer to six decimal places

3) construct a 90% confidence interval and round your answer to the nearest whole number

so 90% confidence interval ( -336 , -6)