This page lists all of the tutorials available on Statology.

Introduction to Statistics

Descriptive vs. Inferential Statistics: What’s the Difference?
Statistic vs. Parameter: What’s the Difference?
Levels of Measurement: Nominal, Ordinal, Interval and Ratio

Descriptive Statistics
Measures of Central Tendency – Mean, Median, and Mode
How Do Outliers Affect the Mean?
Measures of Dispersion – Range, Interquartile Range, Variance, and Standard Deviation
Is the Interquartile Range (IQR) Affected By Outliers?
Can Kurtosis Be Negative?
SOCS: A Helpful Acronym for Describing Distributions
Kendall’s Tau: Definition + Example

Visualizing Data
Stem and leaf plots
How to Find Conditional Relative Frequency in a Two-Way Table

Dixon’s Q Test for Detecting Outliers
Relative Frequency Histogram: Definition + Example
How to Find Class Midpoints in a Frequency Distribution

Theoretical Probability: Definition + Examples
Posterior Probability: Definition + Example
How to Interpret Odds Ratios

Study Design
Sampling Methods
Snowball Sampling: Definition + Examples
What is a Representative Sample and Why is it Important?
Random Selection vs. Random Assignment
Confidentiality vs Anonymity: What’s the Difference?
Understanding Lurking Variables: An Explanation & Examples
Matched Pairs Design: Definition + Examples
Nonresponse Bias: Explanation, Examples, & How to Prevent It
Undercoverage Bias: Explanation, Examples, & How to Prevent It
Pseudoreplication in Statistics: An Explanation, Examples, & What to Do About It
A Simple Explanation of Internal Consistency
Treatment Diffusion: Definition + Example
Split-Half Reliability: Definition + Examples
A Guide to the Benjamini-Hochberg Procedure

Random Variables
Discrete Random Variables
Continuous Random Variables
CDF vs. PDF: What’s the Difference?
The Normal Distribution
Empirical Rule (Practice Problems)
Can a Z-Score Be Negative?
Converting Between Z-Scores and Percentiles Using the Normal Distribution
Combining Normal Random Variables
Binomial Experiments: An Explanation + Examples
A Simple Explanation of Continuity Correction in Statistics

Sampling Distributions
What is a Sampling Distribution?
Understanding the Central Limit Theorem

Confidence Intervals
Introduction to Confidence Intervals
Confidence Interval for a Mean
Confidence Interval for a Difference in Means
Confidence Interval for a Proportion
Confidence Interval for a Difference in Proportions
Bootstrapping in Statistics
How to Create a Confidence Interval Using the F Distribution

Hypothesis Testing
Introduction to Hypothesis Testing
How to Conduct a One Sample t Test
How to Calculate a P-Value from a T-Test By Hand
Hypothesis Testing for a Difference in Means
A Guide to Welch’s t-test (When to Use it + Examples)
Hypothesis Testing for a Difference in Paired Means
Hypothesis Testing for a Proportion
Hypothesis Testing for a Difference in Proportions
Three Ways to Find a P-Value from a t Statistic
Mann-Whitney U Test
How to Perform the Wilcoxon Signed Rank Test
How to Interpret a P-Value of 0.000 
An Explanation of P-Values and Statistical Significance
A Simple Explanation of Statistical vs. Practical Significance
Effect Size: What It Is and Why It Matters
Bayes Factor: Definition + Interpretation

Chi-Square Tests
Chi-Square Test for Goodness of Fit
Chi-Square Test for Homogeneity
Chi-Square Test for Independence
Chi-Square Test vs. t-Test: What’s the Difference?
Three Ways to Calculate Effect Size for a Chi-Square Test

Pearson Correlation Coefficient
What is Considered to Be a “Strong” Correlation?
How to Read a Correlation Matrix
Introduction to Simple Linear Regression
The Four Assumptions of Linear Regression
Testing the Significance of a Regression Slope
How to Read and Interpret a Regression Table
How to Interpret Regression Coefficients
A Simple Guide to Understanding the F-Test of Overall Significance in Regression
Understanding the Standard Error of the Regression
How to Calculate Residuals in Regression Analysis
What is a Good R-squared Value?
Understanding Heteroscedasticity in Regression
A Guide to Multicollinearity in Regression
How to Interpret the C-Statistic of a Logistic Regression Model
What is a Criterion Variable? (Explanation + Examples)
What is a Brier Score?

How to Check ANOVA Assumptions
Kruskal-Wallis Test
One-Way Repeated Measures ANOVA
A Guide to Using Post Hoc Tests with ANOVA
Understanding the Differences Between ANOVA, ANCOVA, MANOVA, and MANCOVA
What is the Difference Between a T-test and an ANOVA?

Matrix Algebra
Matrix Multiplication: (2×2) by (2×2)
Matrix Multiplication: (2×2) by (2×3)
Matrix Multiplication: (3×3) by (3×2)

Time Series
Ljung-Box Test: Definition + Example

Maximum Likelihood Estimation
Maximum Likelihood Estimation (MLE) for a Uniform Distribution