posted by Cam .
A company with two plants producing the same product, but with two slightly different manufacturing processes, conducted a sample study at each of the two plants with the following results: The sample statistics from the first group are: n = 40, x-bar = 18, s = 4.2. The sample statistics from the second group are: n = 50, x-bar = 20, s = 4. In testing the hypothesis that the mean time to produce the product is the same at both plants, what is the p-value of the test?
P-value = P(Z = -2.29) = 0.0219