Basic Computation: Testing m1  m2 A random sample of 49 measurements from a population with population standard deviation 3 had a sample mean of 10.

An independent random sample of 64 measurements from a second population with population standard deviation 4 had a sample mean of 12.

Test the claim that the population means are different. Use level of signifi cance 0.01.

(a) Check Requirements What distribution does the sample test statistic follow?

Explain.

(b) State the hypotheses.

(c) Compute x1  x2 and the corresponding sample test statistic.

(d) Find the P-value of the sample test statistic.

(e) Conclude the test.

(f) Interpret the results.

(g) Find a 99% confi dence interval for m1  m2. Explain the meaning of the confi dence interval in the context of the problem.