Mann Whitney U Test

Question 1

Checklist

Answer 1

Ordinal data

Independent measures design

Test for difference

Question 2

Calculation steps

Answer 2

1. Rank scores from both conditions together.
2. Calculate sum of ranks for condition 1 (R1) and condition 2 (R2)
3. Then use formula

n1: Number of P’s in condition 1
n2 Number of P’s in condition 2

4. Smallest of U, or U₂ is calculated value of U

Question 3

Formula

Answer 3

Question 4

Critical value

Answer 4

Check critical value table based on 1-tailed/2-tailed hypothesis, significance level and n₁ & n₂

Question 5

Significance

Answer 5

If the calculated U value is less than or equal to the critical U value the result is significant = reject Null Hypothesis. If the calculated U value is greater than the critical U value the result is not significant accept Null Hypothesis.

Question 6

Example

Answer 6