Some researchers are doing a two mean pooled t test They have two samples with sizes n 25 and n 13 The population standard deviations are unknown but assumed to be equal so the sample standard deviations are found and used to calculate a pooled standard deviation sp For sample 1 s1 13 2 and 28 For sample 2 s2 14 2 and 2 37 What are the test statistic t and the degrees of freedom to perform this test Select the correct answer below if Sp 13 542 then t df 36 If s 13 542 then t df 36 If sp 13 542 then t df 38 If sp 13 542 then t df 36 25 13 13 542 25 13 13 542 28 37 13 542 V 28 1 28 37 28 37 13 542 2 59 3 54 2 65 1 94