5. Summary

About this Lecture

Lecture

In this lecture, we think about how these descriptive statistics can be summarised, focusing in particular on: (i) reiterating the role of descriptive statistics as to summarise datasets which would otherwise be too large and/or complicated to easily interpret; (ii) the inherent problem of there being more than one measure of central tendency and spread, leading to a question of which one is appropriate to use; (iii) the limitations of nominal data being only appropriate for the mode to be its measure of central tendency; (iv) the median requiring ordering the scores from smallest to largest, meaning that it can be used on at least ordinal level data; (v) the mean and standard deviation requiring adding scores together, meaning that they are only appropriate for interval level data and above; (vi) the influence of outlying data points on each of the measures of central tendency; (vii) addressing the issue of the mean not necessarily being representative of the actual typical score within the dataset.

Course

In this course, Professor Dominic Dwyer (Cardiff University) explores descriptive statistics. In the first lecture, we think about why descriptive statistics are important. In the second lecture, we think about the mode and its representation of the most common score. In the third lecture, we think about the median and how it is only minimally sensitive to outlying scores. Next, we think about the mean and standard deviation, exploring how to calculate each one. In the fifth and final lecture, we think about how these different measures of central tendency and dispersion can be appropriate for different datasets.

Lecturer

Professor Dominic Dwyer is the chair for the BSc and MSc exam boards in the School of Psychology at Cardiff University. Professor Dwyer teaches introductory statistics for undergraduate years one and two. Professor Dwyer’s research is primarily focused on how animals and people learn, as well as how that learning is expressed as behaviour. Some key focus areas of this research are computational modelling, neurodegenerative disorders, and the assessment of individual differences. Some of Professor Dwyer’s recent publications include 'EXPRESS: Instrumental responses and Pavlovian stimuli as temporal referents in a peak procedure' (2022) and 'Face masks have emotion-dependent dissociable effects on accuracy and confidence in identifying facial expressions of emotion' (2022).