Use the given information to find the number of degrees of​ freedom, the critical values χ2L and χ2R​, and the confidence interval estimate of σ. It is reasonable to assume that a simple random sample...

Use the given information to find the number of degrees of​ freedom, the critical values χ2L and χ2R​, and the confidence interval estimate of σ. It is reasonable to assume that a simple random sample has been selected from a population with a normal distribution.
Nicotine in menthol cigarettes 99​% ​confidence; n=20​, s=0.26 mg.

df=19
(Type a whole​ number.)

χ2L=
​(Round to three decimal places as​ needed.)

χ2R=
​(Round to three decimal places as​ needed.)

The confidence interval estimate of σ is mg<><>
​(Round to two decimal places as​ needed.)