The Times of First Sprinkler Activation for a Series of Tests

Essay

The times of first sprinkler activation for a series of tests with fire prevention sprinkler systems using an aqueous film-forming were (in sec). $\begin{array} { l l l l l l l l l l l l l } 28 & 42 & 23 & 28 & 24 & 36 & 31 & 34 & 25 & 28 & 29 & 23 & 25\end{array}$ The system has been designed so that "true" average activation time is at most 25 sec under such conditions. Does the data strongly contradict the validity of this design specification? Test the relevant hypotheses at significance level .05 using the P-value approach.