Question

N = 20

Answer 1

Answer:

A. 30.144

Step-by-step explanation:

This is a Chi-Squared test

Given:

• $n=20$
• $s=18$
• $\textsf{H}_0:\sigma^2=384$
• $\textsf{H}_1:\sigma^2 > 384$
• The significance level is 5%, so $\alpha= 0.05$

To use the Chi-Square distribution table, you need to know two values:

• Degrees of freedom = (n - 1)
• Significance level

Degrees of Freedom = n - 1 = 20 - 1 = 19

The significance level is 5%, so $\alpha= 0.05$

This is a one-tailed test since $\textsf{H}_1:\sigma^2 > 384$ so Upper tail area = 0.05

Reading from the table (attached), the critical value is:  30.144

(This means that we reject $\textsf{H}_0$ if the test statistic is greater than 30.144)