Writing a Psychology Report: Sections Explained
Half of all published psychology papers that use significance testing contain at least one p-value that does not match its own test statistic (Nuijten…
Tag: AQA psychology
Measures of Central Tendency and Dispersion in Psychology
In 1907 Francis Galton lined up 787 guesses of an ox's weight. The middle guess, the median, was 1,207 lb. The ox weighed 1,198 lb (Galton, 1907). Cho…
Peer Review in Psychology: Process, Types and Evaluation
In 1982, two psychologists resubmitted 12 already-published papers to the journals that had printed them, under made-up names. Peer review spotted onl…
Sampling Methods in Psychology: 5 Techniques With Examples
In six leading psychology journals, 96% of studies relied on samples from Western industrialised countries, which hold about 12% of the world's popula…
Spearman’s Rho: Formula, Worked Example and Table
Spearman's rho was invented by a psychologist, yet the rank formula Charles Spearman printed in 1904 is not the one students learn today. His version …
Wilcoxon Signed-Rank Test: Formula, Worked Example and Table
In 1945 the chemist Frank Wilcoxon introduced the Wilcoxon signed-rank test in a four-page paper and tried it on Darwin's maize plants. It reached the…
Mann-Whitney U Test: Formula, Worked Example and Table
The Mann-Whitney U test is often described as a test of medians, but it is not one. Two groups with identical medians can still produce a significant …
Chi-Squared Test in Psychology: Formula, Example, Table
For the first twenty-two years of its life, the chi-squared test used the wrong degrees of freedom. Karl Pearson gave a 2x2 table 3 instead of 1, unti…
Levels of Measurement: Nominal, Ordinal and Interval
Levels of measurement decide which statistical test you are allowed to run, and AQA devotes 25 to 30 per cent of the entire Psychology assessment to r…
Which Statistical Test to Use in Psychology: A Decision Guide
In a review of 513 neuroscience papers, of the studies where a particular comparison mattered, 79 used the wrong statistical procedure and only 78 use…