Mann- Whitney U Test

Question 1

Checklist for using this test:

3

Answer 1

1- ordinal or interval data is produced by DV

2- independent measures design

3- exploring a difference between each condition

Question 2

What happens if two or more of the rating scores are the same?

Answer 2

Add the ranks together, then divide by how many of the scores are the same

E.g rank 2 and rank 3 = 5

4
4

5/ 2 = 2.5

Question 3

How do you find R1 and R2?

Answer 3

Add up all the ranks in R1 and all the ranks in R2

Question 4

Critical value:

Answer 4

A value taken from a statistical table, which must be reached in order for results to be significant

Question 5

Observed value:

Answer 5

The number produced after the various steps and calculations for a statistical test has been carried out

Question 6

What is the formula for the observed u value?

Answer 6

U1= R1- n1(n1+1)/ 2

n= number of participants

You have to use the smaller number out of R1 and R2

Question 7

What happens if the observed u value is less that the critical value?

Answer 7

The null hypothesis can be rejected

If observed u value is more, than the null can be accepted

Question 8

Step by step guide:

Answer 8

1. check using checklist that it is Mann Whitney U test
2. rank scores
3. if some ranks are the same, add ranks, divide by number of participants with the same rank
4. Add up from from section A/ condition A- this is then R1- do the same for condition B, this is R2.
5. Use the formula provided to work out the observed value (use the smallest total out of R1 and R2)- the answer can be written as U1 or U2
6. if observed value is less than critical u value, null hypothesis can be rejected