Correlations

Question 1

What is a correlation?

Answer 1

The relationship between two co-variables

There is no independent/ dependent variable

Use them to test a hypothesis between two variables

Question 2

How to use correlations?

Answer 2

Plot the variables on a scatter graph to find a positive, negative or no correlation.

Use spearman’s rank to test for significance.

Question 3

Correlation coefficient

Answer 3

Measured from -1 to +1

Calculated using spearman’s rank

A significant correlation is +0.8

May need a coefficient of higher significance e.g. +0.05 when testing medicines etc… as need high chance that the relationship is significant.

Question 4

Correlations does not equal causation

Answer 4

There may be an intervening variable making it appear like there is a cause-effect between co-variables.

E.g. There is a strong correlations between shark attacks and ice cream sales, but it’s likely just hot weather making people more likely to buy ice cream and swim in the ocean