Question

A random sample of 49 measurements from one population had a sample mean of 13, with sample standard deviation 3. An independent random sample of 64 measurements from a second population had a sample mean of 15, with sample standard deviation 4. Test the claim that the population means are different. Use the level of significance 0.01.

Using  s₁ = 3 and s₂ = 4, we can compute the t value corresponding to the test statistic  x₁ − x₂ = −2. Recall that  n₁ = 49

and  n₂ = 64.

We will also need the degrees of freedom for this sample statistic, which is given by the smaller of n₁ − 1 and n₂ − 1. Since

n₁ − 1 = 48 and n₂ − 1 = 63,

What are the D.F degrees of freedom?

Answer 1