Question 1129450
t df=23,0.975=2.069
s=7.1
ts/sqrt(n) is half interval or 2.069*7.1/sqrt(24)=3.0 ANSWER
(27.8, 33.8)units minutes

C 
The purpose of a confidence interval is to define where the true mean lies, with a certain degree of confidence.  The true mean is usually unknown and unknowable and either lies in or out of the interval.  We don't know which, and it is a 100-0 type of issue, which is why we use confidence for where we think the true mean lies, not a probability.