Question

According to a recent poll, 25% of adults in a certain area have high levels of cholesterol. They report that such elevated levels "could be financially devastating to the regions healthcare system" and are a major concern to health insurance providers. According to recent studies, cholesterol levels in healthy adults from the area average about 210 mg/dL, with a standard deviation of about 30 mg/dL, and are roughly Normally distributed. Assume that the standard deviation of the recent studies is accurate enough to be used as the population standard deviation. If the cholesterol levels of a sample of 46 healthy adults from the region is taken, 210 mg/dL is the mean and 4.42 mg/dL is the standard deviation of the sampling distribution. If the sample size were increased to 110, the mean of the sampling distribution would __________.

a. remain as 210

b. remain as 30

c. change to 150

d. change to 3.34

Answer 1

When a sample size is taken from a normal distribution . It will be distributed with the same mean as the population mean regardless of its size .

So mean is independent of sample size . Which is same as population mean

Here population mean is 210 mg/dL and it will remain same for the sample of any size

So answer is REMAIN AS 210 OPTION ( a)