Question

The times of first sprinkler activation for a series of tests with fire prevention sprinkler systems using an aqueous film-forming were (in sec): 25, 31, 21, 24, 21, 23, 16, 29, 17, 27, 15, 23, 19. The system has been designed so that true average activation time is at most 20 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.

A. Moderate statistical significance

B. Strong statistical significance

C. No statistical significance

D. Very strong statistical significance

Answer 1

	Values ( X )
	25	6.8403
	31	74.2251
	21	1.9171
	24	2.6095
	21	1.9171
	23	0.3787
	16	40.7631
	29	43.7635
	17	28.9939
	27	21.3019
	15	54.5323
	23	0.3787
	19	11.4555
Total	291	289.0767

Mean

Standard deviation

To Test :-

H0 :-

H1 :-  

Test Statistic :-


t = 1.7518

Test Criteria :-
Reject null hypothesis if


Result :- Fail to reject null hypothesis

Decision based on P value
P - value = P ( t > 1.7518 ) = 0.9474
Reject null hypothesis if P value < level of significance
P - value = 0.9474 > 0.05 ,hence we fail to reject null hypothesis
Conclusion :- Fail to reject null hypothesis

There is insufficient evidence to support the claim that true average activation time is at most 20 sec at 5% level of significance.