Aims and Hypotheses in Psychology: Directional vs Non-Directional
In standard psychology papers, 96% of first hypotheses are supported. In Registered Reports, where the hypothesis is fixed before any data exist, only…
Tag: statistical significance
The Sign Test: Formula, Worked Example and Critical Values
In 1710, a royal physician counted London christening records for 82 straight years, found boys outnumbered girls every single year, and published wha…
T-Tests in Psychology: A Complete Guide
Roughly one in four p-values published across major psychology journals comes from a t-test — making it the single most-used statistical test for comparing two…
What Is a Correlation Coefficient? Pearson’s r and Psychology Statistics
A correlation coefficient of just 0.3 counts as a strong finding in personality psychology, yet most people misread what Pearson’s r actually proves about cause…
Statistical Significance: P-values, Errors & Effect Sizes Guide
Master statistical significance with our comprehensive guide to p-values, Type I/II errors, and effect sizes for evidence-based decisions.