Correlations and Associations

Wikis > Research > Statistics > Statistical Tests > Correlations and Associations

Correlation coefficients quantitatively describe the strength and direction of the relationship between two variables. Looks for a linear association between continuous variables. For ordinal or interval data – the correlation coefficient (r) can be used to measure the degree of association between them. ‘0’ indicates the absence of a correlation. ‘-1’ or ‘+1’ indicates a perfect correlation.
Referred to as Pearson’s product moment correlation coefficient when based on the original data or Spearman’s rank correlation coefficient when based on ranks of the original data. Pearson’s correlation is based on the assumption that the data is normally distributed – if not use Spearman’s rank correlation.
Correlations do not imply causation.

Correlations should not be used when:
• The relationship between variables is not linear (check with scatter plot)
• Influential outliers are in the data
• When there is more than one distinct group in the data
• Samples are not independent of one another

Phi coefficient:
Used when variables are dichotomous eg 0 or 1 Find Weird and Wonderful Books at AbeBooks

We have not yet got to this page to finish it yet. We will eventually. Please contact us if you have something to contribute to it or sign up for our newsletter or like us on Facebook and Instagram or follow us on Twitter.

Page last updated: @ 3:10 am

Comments are closed.