Assume that we want to construct a confidence interval. Do one of the following, as appropriate: (a) find the critical value tα/2, (b) find the critical value zα/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=253, x¯¯¯=31.3 hg, s=7.7 hg. The confidence level is 95%.

Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. tα/2= (Round to two decimal places as needed.)
B. zα/2= (Round to two decimal places as needed.)
C. Neither the normal distribution nor the t distribution applies.