Question

38 major league baseball players average velocity is 91.68 mph, standard deviation is 2.373.

a) is there evidence a pitch is different from 93 mph?

b) without computing the CI, would a 95% CI include 93 mph?

Answer 1

Part a)

H0 :-  

H1 :-  

Test Statistic :-


t = -3.429

Test Criteria :-
Reject null hypothesis if


Result :- Reject null hypothesis

Decision based on P value
P - value = P ( t > 3.429 ) = 0.0015
Reject null hypothesis if P value < level of significance
P - value = 0.0015 < 0.05 ,hence we reject null hypothesis
Conclusion :- Reject null hypothesis

There is sufficient evidence to support the claim that pitch is different from 93 mph.

Part b)

No, since in part a) we are reject H0, it means in 95% CI does not contain the value .