Compare means between two groups with Student's or Welch's t‑test, including Cohen's d effect size, normality tests, and power analysis
Independent samples t‑test comparing exactly two groups with comprehensive diagnostics.
Levene's test determines Student's (equal) or Welch's (unequal) t‑test automatically.
Standardized effect size with interpretation (negligible, small, medium, large) and power analysis.
Your dataset needs a value_column (numeric values to compare) and a group_column (must have exactly 2 unique groups). Each row represents one observation.
Statistical tests included: Shapiro‑Wilk normality test for each group, Levene's test for equal variances, and power analysis based on observed effect size.
Configurable options: Test type (two‑sided, less, greater), confidence level (default 95%), and variance assumption (default uses Welch's test).
From checks to effect sizes
Shapiro‑Wilk test for normality in each group; Levene's test for equal variances determines method.
T‑statistic with degrees of freedom, p‑value, confidence interval, and Cohen's d effect size.
Box plots, density curves, Q‑Q plots, plus summary statistics and power analysis results.
Compare two groups with comprehensive diagnostics—not just significance, but effect size, power, and assumption validation.
The tool automatically validates assumptions with Shapiro‑Wilk and Levene's tests, calculates Cohen's d with magnitude interpretation, provides power analysis to assess sample adequacy, and generates multiple visualizations including box plots, density curves, and Q‑Q plots for normality assessment.
Note: Tool requires exactly 2 groups. Uses Welch's t‑test by default (robust to unequal variances). Reports when normality assumptions are violated.