10-19. + Go Tutorial The diameter of steel rods manufac- tured on two different extrusion machines is being investigated. Two random samples of sizes n₁ = 15 and n₁ = 17 are selected, and the sample means and sample variances are ₁ = 8.73, s = 0.35, x2 = 8.68, and s2² = 0.40, respectively. Assume that σ = 0 and that the data are drawn from a normal distribution. (a) Is there evidence to support the claim that the two machines produce rods with different mean diameters? Use α = 0.05 in arriving at this conclusion. Find the P-value. (b) Construct a 95% confidence interval for the difference in mean rod diameter. Interpret this interval.