Question

Last year, the standard deviation of the ages of the students at UA was 1.8 years. Recently, a sample of 31 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. The null hypothesis is

Answer 1

Answer: $H_0: \sigma=1.8$

Step-by-step explanation:

Let $\sigma$ represents the standard deviation .

Given : Last year, the standard deviation of the ages of the students at UA was 1.8 years.

The researcher 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.

We know that the null hypothesis always contains the equal signs, then the null and alternative hypothesis is given by :-

$H_0: \sigma=1.8\\\\ H_a:\sigma\neq1.8$