In: Statistics and Probability
state the critical values for a two-independent same t-test given the following conditions:
a. two-tailed test a=.01, total df=26
b. one-tailed test, lower tail critical a=.01,df=15 for each group
c. two- tailed test, a=.05, n=12 in each group
d.one-tailed test, upper tail critical, a=.05 n for both groups combined is 30
a) For 26 degrees of freedom, we get from the t distribution tables:
P( t26 < 2.779) = 0.995
Therefore, P( -2.779 < t26 < 2.779) = 0.99
Therefore -2.779, 2.779 are the critical values here.
b) For a one tailed test, for 15 degrees of freedom, we get from the t distribution tables:
P( t15 < -2.602 ) = 0.01
Therefore -2.602 is the required critical t value here.
c) For n - 1 = 11 degrees of freedom, we get from the t
distribution tables that:
P( t11 < 2.201) = 0.975
Therefore -2.201, 2.201 are the required critical values here.
d) For n - 2 = 28 degrees of freedom, we get from the t distribution tables:
P( t28 < 1.701) = 0.95
Therefore 1.701 is the required critical value here.