Exhibit 11-1
Last year, the standard deviation of the ages of the students at UA was 1.8 years. Recently, a sample of 61 students had a standard deviation of 2.1 years. We are interested in testing to see if there has been a significant change in the standard deviation of the ages of the students at UA.
-Refer to Exhibit 11-1. The test statistic is
A)44.08
B)79.08
C)81.67
D)3.24

Question

Quizplus · Accepted Answer

The test statistic for testing a change in standard deviation is calculated using the chi-square distribution: χ² = (n-1)s²/σ², where n is the sample size, s is the sample standard deviation, and σ is the population standard deviation. Here, χ² = (61-1)(2.1)²/(1.8)² = 81.67.

Exhibit 11-1 Last Year, the Standard Deviation of the Ages of the of the Students