correlation

what is correlation?

a technique used to examine the relationship between two variables; measure the strength of the relationship

positive correlation

as one variable increases, the other also increases

negative correlation

as one variable increases, the other decreases

no correlation

no relationship between the variables

non-directional correlation

there will be a correlation

directional correctional

there will be a positive/negative correlation

null correlation

there will be no significant correlation

correlation strength: practicality

- can be used when impractical to manipulate variables experimentally

- any correlations found can form the basis for later experimental research

correlation strength: secondary data

- can use already existing data

- quicker to carry out research than primary research: generalise own data first

correlation weakness: causation