Assume that we want to construct a confidence interval. Do one of the following, as appropriate: (a) find the critical value

t/2,

(b) find the critical value

z/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=287,

x=30.5

hg,

s=7.4

hg. The confidence level is

99%.