Use the Given Degree of Confidence and Sample Data to Find

Multiple Choice

Use the given degree of confidence and sample data to find a confidence interval for the population standard deviation σ.
Assume that the population has a normal distribution. Round the confidence interval limits to the same number of decimal places as the sample standard deviation.
-A sociologist develops a test to measure attitudes about public transportation, and 27 randomly selected subjects are given the test. Their mean score is 76.2 and their standard deviation is 21.4. Construct the 95% Confidence interval for the standard deviation, σ, of the scores of all subjects.

A) $16.6 < \sigma < 28.6$
B) $17.2 < \sigma < 27.2$
C) $16.9 < \sigma < 29.3$
D) $17.5 < \sigma < 27.8$