Question

Scientists collect data on the blood cholesterol levels (milligrams per deciliter of blood) of a random sample of $24$laboratory rats. A $95\%$confidence interval for the mean blood cholesterol level $\mu$is $80.2$to $89.8$. Which of the following would cause the most worry about the validity of this interval?

a. There is a clear outlier in the data.

b. A stem plot of the data shows a mild right skew.

c. You do not know the population standard deviation $\sigma$.

d. The population distribution is not exactly Normal.

e. None of these are a problem when using a $t$ interval.

Short answer

Option (a) is correct.

Step-by-step solution

Given Information

It is given that sample of $24$blood cholesterol levels is taken.

Explanation

Strong outliers and strong skewness is the problem for using $t$procedures.

Assuming $\sigma$as standard deviation in $t$procedure.

Most suitable option is (a) for not worrying about validity of interval. Clear outlier in data is there.