Mathematical Tests

Question 1

Mann Whitney U

• tests significance of the difference between the two conditions when an independent design has been used

Answer 1

S= €(a-ā)^2
———
n-1

S- standered deviation 
€- sum of
a- data
ā- mean
n- num of ppts 

Put into a table, with the headings;

• raw data
• data- mean
• square and add

Question 2

Wilcoxen

• tests significance of the difference between the two conditions when a repeated measure design has been used

Answer 2

Step 1
- find the difference between each set of scores
Step 2
- these differences will need to be ranked
- they are ranked ordering the smallest differences scores to the lowest rank (ignoring signs)
Step 3
- in the difference column, count the number of positive figures and how many negative figures there are
Step 4
- make a calculation with the less frequent sign. Add scores in the ranked order of difference column
Step 5
- calculate the ‘n’ value (number of differences)
Step 6
- match ‘n’ value to the table of critical Wilcoxon signed rank tables

Question 3

Chi Square

• tests to investigate whether distributions or categorical variables differ from one another

Answer 3

Step 1
- add the totals for each column
Step 2
- find the expected frequency
- expected frequency= Raw total x Column total
————————-
Overall total
Step 3
- X^2= € (observed- expected)^2
————————
Expected
Step 4
- calculation of degree of freedom
- df= (number of rows-1) x (number of columns-1)
Step 5
- use df in the look up table