About the lecture

In this lecture, we think about how to decide which statistical test to use, focusing in particular on: (i) some key assumptions of knowledge, so make sure you’ve brushed up on those before continuing (see below); (ii) utilising a visual decision tree to work through how to decide on which of the four main non-parametric test groups you should use to assess whether there is a difference between two reported data sets; (iii) how, in experimental design, there is an independent design which requires a Mann Whitney test and a related design which requires either a Wilcoxon or Sign test; (iv) how, in a non-experimental design, there is a correlation analysis which requires a Spearman’s Rho and a Chi-Square analysis which requires a Chi-Square test.

Assumed knowledge:

Null and alternative hypotheses – See ‘Statistics for Psychologists – Data and the T-test’ by Dr Andrew Bell.

Levels of measurement: nominal ordinal, interval, and ratio – See ‘Statistics for Psychologists – Measurement Levels’ by Professor Dominic Dwyer.

Experimental design: independent and related – See ‘Research Methods – Building an Experiment’ by Dr Eoin O’Sullivan.

Correlational and Chi-Square analysis – See ‘Research Methods – Data Presentation’ and ‘Research Methods – Probability’ by Dr Ayoub Bouguettaya.

About the lecturer

Dr Alison Wadeley is a senior lecturer in the Department of Psychology at Bath Spa University, leading undergraduate teaching on psychological research methods and statistics. Dr Wadeley’s own research focuses on how naturally occurring sleep disruption can impact adult cognitive function, as well as ankylosing spondylitis. Dr Wadeley’s recent publications include ‘Real-world experience of secukinumab treatment for ankylosing spondylitis at the Royal National Hospital for Rheumatic Diseases, Bath’ (2020) and ‘Does measuring the bone mineral density of patients identified as having an osteopaenic X-ray appearance affect bone health treatment decisions? A real-world retrospective analysis’ (2019).