on Estimation 1- A study reports that the mean birth weight of 81 full-term infants is 6.1 pounds. The study also reports "SE = 0.22 pounds." a) What is the margin of error of this estimate for 95% confidence? b) What is the 95% confidence interval for ? c) What does it mean when we say that we have 95% confidence in the interval? d) Recall that SE = . Rearrange this equation to solve for . What was the standard deviation of birth weights in this population? 2- A study takes an SRS from a population of full-term infants. The standard deviation of birth weights in this population is 2 pounds. Calculate 95% confidence intervals for for samples in which: a) n = 81 and = 6.1 pounds b) n = 36 and = 7.0 pounds c) n = 9 and = 5.8 pounds 3- Hemoglobin levels in 11-year-old boys vary according to a Normal distribution with = 1.2 g/dl. a) How large a sample is needed to estimate mean with 95% confidence so the margin of error is no greater than 0.5 g/dl? b) How large a same is needed to estimate with margin of error 0.5 g/dl with 99% confidence