Exhibit 20

Multiple Choice

Exhibit 20.13.An energy analyst wants to test if U.S.oil production is random over time.The analyst has monthly production values for the two years.The analyst finds 12 months are above the median,12 months are below the median,6 runs are below the median,and 5 runs are above the median. Since Refer to Exhibit 20.13.Assume the test statistic R follows a normal distribution.The value of the test statistic is:

A) -2.231
B) -6.868
C) 6.868
D) 2.231