An electrical engineer must design a circuit to deliver the maximum amount of current to a display tube to achieve sufficient image brightness. Within her allowable design constraints, she has developed two candidate circuits and tests prototypes of each. The resulting data (in microamperes) are as follows:

Circuit 1: 251, 255, 258, 257, 250, 251, 254, 250, 248 Circuit 2: 250, 253, 249, 256, 259, 252, 260, 251

(a) Use the Wilcoxon rank-sum test to test H0: 1  2 against the alternative H1: 1 > 2.

Use   0.025.

(b) Use the normal approximation for the Wilcoxon rank-sum test. Assume that   0.05. Find the approximate P-value for this test statistic.