谷歌他们家的 Bard 是这样回答的：
To test variance in one sample when the population is unknown, you can use a t-test. A t-test is a statistical test that is used to compare the means of two groups. In this case, the two groups are the sample data and the hypothesized population variance.
To conduct a t-test, you will need to know the following:
The sample mean: This is the average of the values in your sample data.
The sample standard deviation: This is a measure of how spread out the values in your sample data are.
The degrees of freedom: This is a measure of how much data you have. It is calculated as , where is the number of values in your sample data.n-1n
Once you have this information, you can use a t-table to find the critical value for your test. The critical value is the value that the t-statistic must exceed in order for you to reject the null hypothesis.
The null hypothesis is the hypothesis that the population variance is equal to a certain value. The alternative hypothesis is the hypothesis that the population variance is not equal to that value.
If the t-statistic is greater than the critical value, then you can reject the null hypothesis and conclude that the population variance is not equal to the hypothesized value.
Here is an example of how to conduct a t-test to test variance in one sample when the population is unknown:
Suppose you have a sample of 10 values that has a mean of 50 and a standard deviation of 10. You want to test the hypothesis that the population variance is 100.
The degrees of freedom for this test are .10-1 = 9
The critical value for a two-tailed t-test with 9 degrees of freedom and a significance level of 0.05 is 2.262.
The t-statistic for this test is .(50-100)/(10/sqrt(10)) = -5.26
Since the t-statistic is greater than the critical value, we can reject the null hypothesis and conclude that the population variance is not equal to 100.
It is important to note that a t-test is only valid if the sample data is normally distributed. If the sample data is not normally distributed, then you may want to use a nonparametric test, such as the Welch-Satterthwaite test.