Independent simple random samples are taken to test the difference between the means of two populations whose standard deviations are not known, but are assumed to be equal. The sample sizes are n1 = 25 and n2 = 35. The correct distribution to use is the
A) t distribution with 61 degrees of freedom
B) t distribution with 60 degrees of freedom
C) t distribution with 59 degrees of freedom
D) t distribution with 58 degrees of freedom

Question

Quizplus · Accepted Answer

When the population standard deviations are unknown but assumed equal, the t distribution is used with degrees of freedom calculated as n1 + n2 - 2, which is 25 + 35 - 2 = 58.

Independent Simple Random Samples Are Taken to Test the Difference