Consider a normal population distribution with the value of 0' known. IE use SALT (a) What is the confidence level for the interval )_( :l: 2.880/ 3? (Round your answer to one decimal place.) (b) What is the confidence level for the interval E :l: 1.436/ ? (Round your answer to one decimal place.) (c) What value of z/2 in the CI formula below results in a confidence level of 99.7%? (Round your answer to two decimal places.) (d) Answer the question posed in part (c) for a condence level of 62%. (Round your answer to two decimal places.)