Wilcoxon Signed Ranks Test

Question 1

Checklist for using this test:

3

Answer 1

• ordinal and/ or interval data
• exploring a difference
• repeated measures design

Question 2

How to guide:

7 steps

Answer 2

1- find the difference between each set of data (category 1 and 2)
2-rank the difference (all positive and negative signs (and 0) should be ignored)
(If ranks are same same then + ranks, / by how many)
3- count the positive and negative numbers
(Ignore 0)
4- find the observed value- this is the sum of the scores with the less frequent sign (+/-).
5- calculate the n value (no. Of pps- make sure to ignore any zeros- they do not count as the n value)
6-Match the n value to the table of critical Wilcoxon Signed Ranks value (0.05 significance level)

7- if observed value >critical Wilcoxon value, results are not significant, accept null
If observed value < critical Wilcoxon value, results are significant, reject null

Question 3

When do you reject the null hypothesis?

Answer 3

When the observed value is lower than the critical Wilcoxon value- results are significant

Question 4

When do you accept the null hypothesis?

Answer 4

When the observed value is bigger than the critical Wilcoxon value- results are not significant

Question 5

How do you rank a difference of 0?

Answer 5

You ignore it- it is not included in the n value

Question 6

What do you do if two rank of difference are the same?

Answer 6

Add ranks together

Divide by how many pps with the same rank

Question 7

When ranking, how do you deal with positives and negatives?

Answer 7

You ignore them- the smallest number is the lowest rank.

Question 8

How do you find the observed value?

Answer 8

Find the less frequent sign (+/-)

Add the values in the ranked column of the less frequent sign (last columnof table)