Mann Whitney (U) Test

Mann-Whitney Test (U)

Criteria for Use

Independent Measures Design & Ordinal Level Data

Ua Formula

Condition A

Participant

Rating

Rank

Condition B

Participant

Rating

Rank

1

2

3

4

5

6

4

5

2

9

2

6

3

4

1.5

7.5

1.5

5

1

2

3

4

5

6

12

8

9

10

11

14

11

6

7.5

9

10

12

Total (Ra) =

22.5

55.5

Total (Rb) =

Ub Formula

Writing Your Results

U = 1.5, (Na = 6, Nb = 6) , p ≤ 0.05

Procedure

1. Write out participant scores and rank them all as one

2. Calculate the rank totals (Ra and Rb)

3. Plug these into the above formulae

4. Take U to be the smallest of Ua and Ub