An article in Electronic Components and Technology Conference (2001, Vol. 52, pp. 1167–1171) compared single versus dual spindle saw processes for copper metallized wafers. A total of 15 devices of each type were measured for the width of the backside chipouts, x̅_single = 66.385, s_single = 7.895 and x̅_double = 45.278, s_double = 8.612.

(a) Do the sample data support the claim that both processes have the same chip outputs? Use α = 0.05 and assume that both populations are normally distributed and have the same variance. Find the P-value for the test.

(b) Construct a 95% two-sided confidence interval on the mean difference in spindle saw process. Compare this interval to the results in part (a).

(c) If the β-error of the test when the true difference in chip outputs is 15 should not exceed 0.1, what sample sizes must be used? Use α = 0.05.