Social Science Statistics

Social Science Statistics provides free, registration-free tools, tutorials and a test-selection wizard. Its independent-means t-test accepts at least two observations per group, a significance level and a one- or two-sided alternative. Choose Welch for the documented unequal-variance model or pooled Student for its equal-variance assumption; both require independent observations and approximately normal sampling distributions of means. The action calculates T and P values. The site's published verification compares selected cases with independent references, which does not establish every possible input or interpretation. Power analysis and descriptive summaries are separate tasks.