A government sample survey plans to measure the LDL (bad) cholesterol level of a
ID: 3149444 • Letter: A
Question
A government sample survey plans to measure the LDL (bad) cholesterol level of an SRS of men aged 20 to 34. Suppose that in fact the LDL cholesterol level of all men aged 20 to 34 follows the Normal distribution with mean mew = 115 milligrams per deciliter (mg/dl) and standard deviation sigma = 23 mg/dL. Use Table A for the following questions, where necessary. Choose an SRS of 100 men horn population. What is the sampling distribution of bar x? (Use the units of mg/dL.) What is the probability that bar x takes a value between 112 and 118 mg/dL? This is the probability that bar x estimates mew within plus or minus 3 mg/dL. (Round your answer to three decimal places.) Choose art SRS of 1000 men from this population, How what is the probability that bar x falls within plus or minus 3 mg/dL of mew? The larger sample is much more likely to give an accurate estimate of mew.Explanation / Answer
b) mu+3sd=115+3*0.25=115.75
z=(Xi-Xbar)/s=(115.75-115)/0.25=3
Area corresponding to 3 is 0.4986. The probability is 0.499.