Please help answer the question in the screenshot below.... There are 4 parts

Use the given information to find the number of degrees of freedom, the critical values x" and X? , 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 = 30, s = = Click the icon to view the table of Chi-Square critical values. df = (Type a whole number.) (Round to three decimal places as needed.) XR (Round to three decimal places as needed.) The confidence interval estimate of o is mg