SUMMARIES

• Arithmetic, geometric, and harmonic means, and corresponding confidence intervals
• Medians and percentiles
• Measurement of central tendency
• Skewness and kurtosis
• Confidence intervals
• Means
• Normal
• Exact Poisson
• Proportions
• Exact binomial (Clopper–Pearson)
• Wald
• Wilson
• Jeffreys
• Agresti
• Variance
• Normal
• Bonett
• Ratios, proportions, and totals
• Confidence intervals
• Standard errors
• Over groups
• Robust and cluster–robust SEs
• Intragroup tests

TABLES AND TABULATIONS

• 1- , 2-, n-way
• Pearson’s chi-squared
• Likelihood-ratio chi-squared
• Cramér’s V
• Fisher’s exact (2 x 2 and r x c)
• Goodman and Kruskal’s gamma
• Kendall’s tau
• Cell statistics
• Expected count
• Contribution to Pearson chi-squared
• Contribution to likelihood-ratio chi-squared TABLES OF SUMMARY STATISTICS

• Over groups and/or variables
• Statistics may include mean, count, sum, min, max, range, standard deviation, variance, variation coefficient, standard error of mean, skewness, kurtosis, median, percentiles, and interquartile range
• Results from any summary-statistics command

CREATION OF DATASETS OF SUMMARY STATISTICS

• Statistics by group or subgroup of observations
• Statistics: mean, standard deviation, count, min, max, median, percentiles, and interquartile range

PAIRWISE COMPARISONS OF MEANS

• Pairwise differences in means with tests and confidence intervals

• Multiple-comparison adjustments: Bonferroni, Šidák, Scheffé, Tukey HSD, Duncan, and Student–Newman–Keuls adjustments
• Group comparisons that are significant
• Balanced and unbalanced data

T TESTS

• One sample
• Two independent samples
• Two paired samples
• Based on summary data (ttesti)

Z TESTS

• One sample
• Two independent samples
• Two paired samples
• Support for clustered data
• Based on summary data (ztesti)

TESTS OF PROPORTIONS

• One sample
• Two sample
• Support for clustered data
• Based on summary data (prtesti)

EFFECT SIZES

• Comparison of means
• Cohen’s d
• Hedge’s g
• Glass’s Δ
• Point/biserial correlation
• Confidence intervals
• Variance explained by regression and ANOVA
• Eta-squared—η2
• Omega-squared—ω2
• Confidence intervals

Video – A tour of effect sizes

OTHER COMMON TESTS

• Binomial (one-sample) test
• Bartlett’s test
• Chi-squared (one-sample) variance test
• Variance ratio (two-sample) F test

CORRELATIONS

• Pearson simple and partial
• Semipartial
• Spearman’s rank correlation
• Kendall’s rank correlation
• Intracluster
• Cronbach’s alpha
• Tetrachoric
• Canonical (multivariate) correlations
• Intraclass

FACTOR VARIABLES

• Automatically create indicators based on categorical variables
• Form interactions among discrete and continuous variables
• Include polynomial terms
• Perform contrasts of categories/levels
Watch Introduction to Factor Variables in Stata tutorials