Assume that we want to construct a confidence interval. Do one of the following, as appropriate: (a) find the critical value ta/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=192, x 31.6 hg, s=6.6 hg. The confidence level is 99%. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. OA/2 (Round to two decimal places as needed.) OB. Za/2 (Round to two decimal places as needed.) OC. Neither the normal distribution nor the t distribution applies.