Consider a normal population distribution with the value of known. (a) What is the confidence level for the interval x 2.750/n? (b) What is the confidence level for the interval x 1.420/n? (c) What value of z a/2 in the CI formula below results in a confidence level of 99.3%? (x-12x + 3/2 ) (d) Answer the question posed in part (c) for a confidence level of 76%.