Suppose That You Are Performing A $\chi ^ { 2 }$

Multiple Choice

Suppose that you are performing a $\chi ^ { 2 }$ -test for a population standard deviation. Which of the following statements regarding the distribution of the test statistic is true?

A) If the null hypothesis is true, the test statistic has a chi-square distribution with $\mathrm { df } = \mathrm { n }$ .
B) If the null hypothesis is true, the test statistic has a chi-square distribution with $\mathrm { df } = \mathrm { n } - 1$ .
C) If the null hypothesis is false, the test statistic has a chi-square distribution with $\mathrm { df } = \mathrm { n }$ .
D) If the null hypothesis is false, the test statistic has a chi-square distribution with $d f = n - 1$ .