A fundamental knowledge of the simple measures of central tendency
--the mean, the median, and the mode--is essential to understanding basic statistical inference.
However, the situation is complicated because individual differences across measures of central tendency
, dispersion, or distributional shape can be considerable (Luce, 1986).
Cohen takes an accessible, conversation approach when introducing the conceptual foundations and basic of statistic procedures, a practice he continues with material on frequency tables, graphs, distributions, measures of central tendency
and variability, standardized scores and the normal distribution, hypothesis testing with one or two samples, internal estimation and the t distribution, the t test for two independent sample means, statistical power and effect size, linear correlation and regression, the matched t test, one-way independent ANOVA and two-way ANOVA, multiple regression and its connection to ANOVA, nonparametric statistics, chi-square tests and statistical tests for ordinal data.