Question

Data on the blood cholesterol levels of 24 rats (in milligrams per deciliter) give x = 85 and s = 12. Which of the following would be most worrisome for the validity of a 99% confidence interval for the mean blood cholesterol of rats calculated from this information?

a. the presence of a clear outlier in the raw data
b. a mild skew in the stemplot of the raw data
c. not knowing the population standard deviation

Answer 1

A.

Explanation:

In this question, we are asked to choose from the options, which would be most worrisome for a 99% CI

The correct option is A

In statistics, when we talk about outliers, we are generally referring to data points which are obviously different from other observations. On a plot, these outliers stand at points which are significantly far away from a cluster of the other data points.

Now, due to the fact that an outlier will shift the mean towards itself , thus shifting the confidence interval to its side, this can provide a wrong confidence interval or simply CI.

Thus, option A is the correct answer.