The diameter of steel rods manufactured on two different machines is being investigated. Two random samples of sizes m = 15 and n2 = 17 are selected. Sample means and variances are x1 = 8.73, s, = 0.34, x2 = 8.68, s? = 0.39. Round your answers to two decimal places (e.g. 98.76). (a) Construct a 90% two-sided confidence interval on of / 63: i (b) Construct a 95% two-sided confidence interval on o2 /63: i (c) Construct a 90% lower-sided confidence interval of / o