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

Multiple Choice

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 U statistic is __________

A) 29
B) 45
C) 90
D) 36
E) 43