Hemoglobin levels in 11-year-old boys vary according to a Normal distribution with o 1.2 g/dl. a a) How large a sample is needed to estimate mean u with 95% confidence so the μ margin of error is no greater than 0.5 g/dl? b) How large a same is needed to estimate u with margin of error 0.5 g/dl with 99% confidence?
