Normal dstrubituon

31. Cholesterol The level of cholesterol in the blood J 638 all men aged 20 to 34 follows a Normal distributior with mean 188 milligrams per deciliter (mg/dl) and standard deviation 41 mg/dl. For 14-year-old boys, blood cholesterol levels follow a Normal distributim with mean 170 mg/dl and standard deviation 30 mg/d Suppose we select independent SRSs of 25 men aged 20 to 34 and 36 boys aged 14 and calculate the sample mean cholesterol levels 56M and f3. ((9 Find the standard deviation of the sampling distribu