Psychological Statistics: 2011

Calculating and graphing within-subject confidence intervals for ANOVA

Psychologists are gradually coming round to the view that it is a good idea to present interval estimates alongside point estimates of statistics. The most common statistic reported in psychology research is almost certainly the mean (strictly the arithmetic mean). Presenting an interval estimate for the mean of a single sample is usually quite simple. This is usually done as 95% confidence interval about the mean – and most researchers in psychology are able to calculate this by hand or get their statistical software to calculate and graph it for them.

Extending this to more than one mean introduces an additional layer of complexity.

Sep

A problem of significance

Several people have drawn my attention to a recent article on a common error in published statistical analyses in neuroscience. Sander Nieuwenhuis, Birte Forstmann and Eric-Jan Wagenmakers published (in Nature Neuroscience) a critique of statistical analyses in the neuroscience literature. This paper has been written about by Ben Goldacre and Andrew Gelman (who published an article on the general problem some time ago) - so I won't go into too much detail.

Jan

R: An introduction for psychologists

Here are the slides from the Introduction to R session Danny Kaye and I ran at the BPS Mathematics, Statistics & Computing section CPS Workshop (13 December 2010, Nottingham Trent University).