Question

Where 90% of the area falls between these two t values with 25 degrees of freedom. Show your work.

Answer 1

Ans. Since we are asked 2 t-values with df 25 between which 90% of the area falls , we are left with only one case that is to find the two tailed test value of t (alpha=0.05,df=25)= t .

=P(-t<= T <= t)=0.90

=P(T<=t) - P(T<=-t)=0.90

=1-P(T>t) - ( 1-P(T<=t) ) = 0.90

=1-P(T>t) -1 +(1-P(T>t) = 0.90

=2*P(T>t)= 0.10

= P(T>t)= 0.05

Using the following T- table we get the 2 t-values as -1.708 and 1.708 at 25 df .