Assume that we want to construct a confidence interval. Do one of the following, as appropriate: (a) find the critical value to /2. (b) find the critical value Za/2, or (c) state that neither the normal distribution nor the t distribution applies. Here are summary statistics for randomly selected weights of newborn girls: n = 169, x= 30.7 hg, s =7.1 hg. The confidence level is 90%. . . . Select the correct choice below and, if necessary, fill in the answer box to complete your choice. OA. to/2= (Round to two decimal places as needed.) OB. Za/2 = (Round to two decimal places as needed.) O C. Neither the normal distribution nor the t distribution applies