Question

Find the left critical value for 95% confidence interval for σ with n = 41. 26.509 24.433 55.758 59.342

Answer 1

Answer: 59.342

Explanation:

The chi-square critical values are used to find the confidence interval for σ.

Left critical value =
`\chi^2_(\alpha/2, n-1)` [i.e. chi-square value from chi-square table corresponding to degree of freedom n-1 and significance level of
`\alpha/2`]

To find : left critical value for 95% confidence interval for σ with n = 41.

Significance level :
`\alpha=1-0.95=0.05`

degree of freedom = 41-1=40

Now, the left critical value for 95% confidence interval for σ with n = 41 is the chi-square value corresponding to degree of freedom n-1 and
`\alpha/2=0.025`

=59.342 [from chi-square table ]