Statistics Tutorials and Data Analysis Guides

Internal consistency with Python Reliability Analysis in Python: 7 Essential Steps, Cronbach’s Alpha and Bootstrap CI Reliability analysis in Python evaluates whether a set of measurements…

Model-based internal consistency reliability McDonald’s Omega: Formula, Interpretation and Worked Example McDonald’s omega is a factor-model reliability coefficient for a composite score when item loadings are…

Binary-item internal consistency reliability Kuder Richardson Formula 20: 7 Essential Steps, Formula and Worked Example The Kuder Richardson Formula 20, commonly written as KR-20, estimates the…

Paired-measurement agreement analysis Limits of Agreement: 7 Essential Steps, Formula, Confidence Intervals and Worked Example The limits of agreement method estimates how far two paired measurements…

Dichotomous-item reliability approximation Kuder-Richardson Formula 21: 7 Essential Steps and Example The Kuder-Richardson Formula 21 is a simplified internal-consistency reliability estimate for a test made of…

Multi-rater reliability and agreement Krippendorff’s Alpha: 7 Essential Steps, Formula and Worked Example The Krippendorff’s Alpha coefficient measures agreement by comparing observed disagreement with disagreement expected…

Reliability and item analysis Item Total Correlation: Formula, Interpretation, SPSS, Python, R and Excel The item total correlation measures the Pearson association between each item and…

Same-rater repeatability across fixed sessions Intra-Rater Reliability: 7 Essential Steps, ICC Formula and Worked Example Intra-rater reliability measures how consistently the same rater, examiner, coder, instrument…

Agreement among quantitative ratings Inter Rater Reliability: 7 Essential Steps, ICC Formula and Worked Example Inter rater reliability describes how consistently two or more raters, graders,…

Internal consistency reliability lower bound Guttman’s Lambda-6: 7 Essential Steps, Formula and Worked Example Guttman’s Lambda is a family of six lower-bound reliability coefficients. This guide…