Correlation

Question 1

Describe correlation

Answer 1

• Used when trying to understand how variables are related
• Discovers whether meaningful relationships exist between 2 variables
• Establishes direction of relationships
• Establishes strength of relationship

Question 2

Describe scatter graphs

Answer 2

• In a perfect scatter graph all points fall on line of best fit
• Scatter graphs must be checked before doing inferential statistics
• Show correlation by plotting paired scores to find out what kind of correlation there is between two variables

Question 3

Describe causation

Answer 3

• Correlational designs can cause problems as correlation does not infer causation
• Can cause people make false allegations
• Just because variables are related, doesn’t mean one causes the other

Question 4

Strength of correlation

Answer 4

• Known as the correlation co-efficient
• Can range from -1.00 to +1.00
• Value of 0 = no correlation
• Value of +1.00 = perfect positive correlation
• Value of -1.00 = perfect negative correlation

Question 5

Cohen’s r

Answer 5

r = 0.10-0.29 = weak correlation
r = 0.30-0.49 = moderate correlation
r = 0.5-1.00 = strong correlation