. Suppose you know that the standard deviation of the age of a person that contracted covid is 15.4 years. You randomly sample 120 people who have contracted the virus and compute their mean age to be 37.4 years. you decide to constrtuct a 90% confidence interval for the mean age of some that has contracted the virus. (a) Is there concern that the distribution of ages might not be normally distributed? (b) What is the value of z for a 90% confidence interval? (c) What is the margin of error for the 90% confidence interval? (d) Construct the 90% confidence interval.