Interactive Tools
Learn by Doing
Each book is paired with interactive applications. These tools let you manipulate inputs and see how outputs change. They are designed to make abstract ideas concrete: instead of reading about how sample size affects a confidence interval, you change the sample size and watch the interval move.
The full collection is available at apps.marginoferrormedia.com.
All tools run in the browser. No installation required. No login required.
Featured Tools
Sampling Distribution Explorer
Draw repeated samples from a population and watch the sampling distribution form. Adjust the sample size, population shape, and number of draws. This is the single most important concept in inferential statistics, and it is much easier to understand when you can see it happen.
Confidence Interval Simulator
Generate hundreds of confidence intervals from the same population. See how many capture the true parameter and how many miss. This directly demonstrates what “95% confidence” means, and what it does not mean.
Hypothesis Testing Visualizer
Set up a hypothesis test with adjustable significance level, effect size, and sample size. Watch how the rejection region, p-value, and power change as you adjust each parameter. See the tradeoffs that every test involves.
Regression Playground
Fit regression models to different datasets. Add or remove predictor variables. Check residual plots. See how multicollinearity affects coefficient estimates. A hands-on environment for building regression intuition.
By Book
Margin of Error. Tools for sampling distributions, confidence intervals, hypothesis testing, ANOVA, and regression diagnostics.
Run the Numbers. Interactive code editors and data wrangling exercises that run in the browser.
Good Data Starts Here. Tools for exploring question wording effects, response scale design, and sample size planning for surveys.
Evidence First. Research design comparison tools and effect size calculators.
Make It Visible. Interactive chart builders, perception experiments, and mapping tools.