In constructing a confidence interval for σ2
, a table is used to find the critical values
χ2L and χ2R
for values of n < 101. For larger values of n, the critical values of
χ2
can be estimated by using the formula:
χ2 = 12[ ±zα2 + √2k−1]2
where k is the number of degrees of freedom and
zα2
is the critical z score.

Construct the 90% confidence interval for variance if a random sample of 234 people yields a mean weight of 155 lbs and a standard deviation of 26 lbs.

(round all answers to two decimal places)

I need X2L and X2R, The point estimate σ2, and the confidence interval.