Topic hub
Foundations
Core notation, vocabulary, and concepts for learning statistics, covering populations versus samples, variable types, and summation notation.
Descriptive vs Inferential Statistics: Examples
Descriptive vs inferential statistics differ in what they let you claim: one summarizes your data, the other generalizes beyond it. See worked examples.
Fundamental Statistics: Definition & Basics
Fundamental statistics covers what statistics means, its two branches, and the core math (mean, variance, z-score), with a fully worked example.
Independent vs Dependent Variable: Examples
Independent vs dependent variable, explained plainly: how to spot each one, plus control variables and 10 practice examples with answers.
Levels of Measurement: Nominal, Ordinal, Interval & Ratio
Learn the four levels of measurement — nominal, ordinal, interval, and ratio — and understand the ordinal variable vs nominal distinction with clear examples.
Parameter vs Statistics: Definitions & Symbols
Parameter vs statistics: a parameter describes a whole population, a statistic describes a sample. See the formulas, symbols, and a worked example.
Population vs Sample: Key Differences & Formula
Population vs sample: the key differences, N vs n notation, sampling frames, the population vs sample formula, and why sample variance uses n minus 1.
Proportion in Statistics: Meaning & Formula
A proportion in statistics is the share of a group with a trait, from 0 to 1. Learn the proportion formula, confidence intervals, and hypothesis tests.
Reliability in Statistics: Cronbach's Alpha & Cohen's Kappa
Learn what Cronbach's alpha and Cohen's kappa measure, how to calculate and interpret both, and when to use each reliability statistic in research.
Sampling Methods: Probability & Non-Probability
Sampling methods explained: probability techniques (simple random, systematic, stratified, cluster) vs non-probability sampling, bias, and how to choose.
Simple Random Sampling: How to Draw a Sample
Simple random sampling gives every unit an equal chance of selection. Learn how to draw one by hand, in Excel, Google Sheets, and Python's pandas.
Statistics Symbols Cheat Sheet: All 40+ Signs Explained
A complete statistics symbols cheat sheet: Greek letters, sample vs. population notation, hypothesis testing signs, and probability symbols — all explained.
Types of Bias in Statistics: 12 Biases
Types of bias in statistics include selection, sampling, response, confirmation, and eight more, plus how to catch each one before it skews your results.
Types of Variables: Qualitative vs. Quantitative
Learn to classify types of variables in statistics: qualitative vs quantitative, discrete vs continuous, and how each type shapes your research and analysis.