question attached:

A random sample of 20 chocolate energy bars of a certain brand has, on average, 280 calories per bar, with a standard deviation of 15 calories. Assume that the distribution of the calorie content is approximately normal. Construct a 95% confidence interval for o. Click here to view page 1 of the table of critical values of the chi-squared distribution. Click here to view page 2 of the table of critical values of the chi-squared distribution. The confidence interval is