Correlations Flashcards
What are correlations?
A technique used to investigate the relationship between two variables (co-variables)
How are correlations recorded?
A scatter graph
What do correlations tell us?
The strength and direction of the relationship between variables
Describe a positive correlation
When one variable increases, the other increases
Describe a negative correlation
When one variable increases, the other decreases
Describe no correlation
When there’s no relationship between the variables
What is the correlation coefficient?
A measure of how strong the correlations are. This can be given in a scatter graph or a numerical representation between -1.0 and 1.0 depending on the strength and direction of the relationship between the variables.
Describe what a correlation coefficient of -1 means
A negative relationship and very strong correlation
Describe what a correlation coefficient of +1 means
A positive relationship and a very strong correlation
Describe what a correlation coefficient of of 0 means
No correlation
What are advantages of correlations?
They are a good starting point for research. Correlations tell us that two variables are related and this may give researchers information for future research and lead to experiments
Quick and easy to carry out, particularly when experiments can’t be done, e.g. we cannot force people to smoke to investigate the effects of lung cancer, but we can plot data from those who already smoke.
What are disadvantages of correlations?
It only measures relationships and therefore we cannot determine cause and effect as other extraneous variables could have caused the results, e.g. does stress cause illness or does illness cause stress or is there some other factor affecting both stress and illness?
For the correlation to be informative, a large amount of data is needed.
