Correlation

Question 1

Correlation and use

Answer 1

Relationship between 2 co variables
Investigate strength and direction of relationship

Question 2

Correlation coefficient r

Answer 2

+1 Prefect positive 1v Inc so other inc
-1 perfect negative 1v Inc other dec
0 no correlation
Closer 1 strong and 0 weak

Question 3

Types of hypothesis

Answer 3

One tailed= directional eg sig +ve between
Two tailed= non directional
Null= no sig correlation

Question 4

Steps to calculate correlation

Answer 4

1 hypothesis
2 operationalise 2 co variables
3 plot scatter graph
4 statistical test

Question 5

Cause and effect

Answer 5

No manipulation of variables so imp to claim casual relationship between 2 co variables

Question 6

Strength

Answer 6

I unexpected relationship between 2 variables
J influence further research in particular field eg aggression response to stimuli
E useful conduction preliminary analysis on data so strong correlation justified and casual ruled out

Question 7

Weakness

Answer 7

I can’t prove cause and effect relationships
J intervening variables that explain how co variables are linked eg temp explains + correlation betw forest fires and ice cream sales
E not explained by correlation