18) Use the Wilcoxon rank-sum approach to test the claim that the sample student grade averages at two colleges come from populations with the same median. The sample data is listed below. Use a 0.05 level of significance, and assume that the samples were randomly selected. Find the critical values and express the rejection region:
College A 3.2   4.0   2.4   2.6   1.8
College B 2.4   1.9   2.8   3.0

A) 13 ≤ T ≤ 27    B) 12 ≤ T ≤ 28    C) T ≤ 12, T ≥ 28    D) T ≤ 13, T ≥ 27