Suppose a research uses the Mann-Whitney test to determine if there is a difference in the volume of text messages sent by a high school student living in a rural area versus an urban area during the month of December.Eight rural high school students and 9 urban high school students were included in the study.If, among all 17, the sum of the ranks W₁ produced from the rural high school students is 72, the U₁ statistic is __________ A)29 B)45 C)90 D)36 E)43

Question

Quizplus · Accepted Answer

The U statistic for the Mann-Whitney test can be calculated using the formula U = n1*n2 + (n1*(n1+1))/2 - WS, where n1 and n2 are the sample sizes of the two groups, and WS is the sum of the ranks for one of the groups. Here, n1 = 8 (rural students), n2 = 9 (urban students), and WS = 72 (sum of the ranks for rural students). Plugging these values into the formula gives U = 8*9 + (8*(8+1))/2 - 72 = 72 + 36 - 72 = 36.

Suppose a Research Uses the Mann-Whitney Test to Determine If