A random sample of n1 = 10 regions in New England gave the following violent crime rates (per million population). x1: New England Crime Rate 3 3.3 4.4 3.6 3.3 4.1 1.8 4.8 2.9 Another random sample of n2 = 12 regions in the Rocky Mountain states gave the following violent crime rates (per million population). x2: Rocky Mountain Crime Rate 3.6 4.4 4.5 5.2 3.3 4.8 3.5 2.4 3.1 Assume that the crime rate distribution is approximately normal in both regions. Note: If a two-sample t-test is appropriate, for degrees of freedom d.f. not in the Student’s t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value by a small amount and therefore produce a slightly more “conservative” answer. a. Use a calculator to calculate b. What is the value of the sample test statistic? (Test the difference μ1 − μ2. Round your answer to three decimal places.) c. Find the P-value. (Round your answer to four decimal places.) d. Find a 98% confidence interval for μ1 − μ2. (Round your answers to two decimal places.)
