A researcher wants to estimate the mean cholesterol level of people in his city.A random sample of 21 people yields an average cholesterol level of 219,with a margin of error of ±12.Assume the researcher used a confidence level of 90%.

Question

Quizplus · Accepted Answer

The margin of error of ±12 indicates that the true mean cholesterol level in the city could be either 12 units higher or 12 units lower than the sample mean of 219. Since the confidence level is 90%, we can say that we are 90% confident that the true mean lies within the interval [219-12, 219+12], which simplifies to (207, 231). Thus, the correct statement is that the researcher can be 90% confident that the mean cholesterol level for people in his city is between 207 and 231. The other choices are incorrect because they either make incorrect statements about the sample, the population, or the confidence interval.

A Researcher Wants to Estimate the Mean Cholesterol Level of People