Use the given information to find the number of degrees of freedom, the critical values ? and XR, and the confidence interval estimate of o. It is reasonable to assume that a simple random sample has been selected from a population with a normal distribution. Nicotine in menthol cigarettes 90% confidence; n = 26, s = 0.25 mg. Click the icon to view the table of Chi-Square critical values. df =(Type a whole number.) x2 = (Round to three decimal places as needed.) X'R =(Round to three decimal places as needed.) The confidence interval estimate of a is mg co