5. The T-test

About this Lecture

Lecture

In this lecture, we think about the t-test, focusing in particular on: (i) the history of the t-test and its origins within Guinness beer; (ii) how a t-distribution differs from the afore discussed normal (or Gaussian) distribution; (iii) degrees of freedom and the theory behind the statistic; (iv) the three types of t-test, and the differences between each one.

Course

In this course, Dr Andrew Bell (Kings College London) introduces statistics for psychologists and the t-test. In the first lecture, we are introduced to the different types of data which might be analysed for a scientific study. In the second lecture, we think about descriptive statistics, specifically mean, variance, and standard deviation. In the third lecture, we explore data distributions, working through normal (or Gaussian), leftward skewed, and rightward skewed graphs. Next, we think about null hypothesis significance testing (NHST), highlighting the importance of understanding what is meant by rejecting and not rejecting a hypothesis. In the fifth lecture, we think about the t-test, outlining the similarities and differences between a one sample, independent samples, and paired samples test. In the sixth and final lecture, we work through an example of each of the three t-tests to solidify our understanding.

Lecturer

Dr Andrew Bell is a lecturer in cognitive neuroscience in the Institute of Psychiatry, Psychology and Neuroscience at King’s College London. Dr Bell works in the neuroimaging department and focuses his teaching on statistics and statistical techniques. Dr Bell is a senior fellow of the Higher Education Academy and has published a review of animal lesion techniques used by researchers of human neuropsychology. Dr Bell’s recent publications include ‘Preserved extrastriate visual network in a monkey with substantial, naturally occurring damage to primary visual cortex’ (2019) and ‘Viewing ambiguous social interactions increases functional connectivity between frontal and temporal nodes of the social brain’ (2021).