How these work
Each unit is a complete lesson: a narrated walkthrough you can pause and replay, figures built to be manipulated rather than just looked at, and a short check at the end. Open one and it talks you through the section; choose Present instead and the narration stays off, which is the version to put on a projector.
Sections follow Elementary Statistics, but nothing here depends on having that book.
Units
Sampling & Types of Data
Why a sample has to be random, what goes wrong when it isn't, and how to tell a qualitative variable from a quantitative one.
Graphical Summaries
Frequency tables, bar graphs and histograms — and how the choice of class width changes the story a histogram tells.
Measures of Center and Spread
Mean against median, and why deviations get squared before they are averaged.
Measures of Spread and Measures of Position
Standard deviation and the Empirical Rule, then z-scores and quartiles for locating a single value within a distribution.
Least Squares Regression and Correlation
What r measures, what it misses, and where the line of best fit comes from.
Basic Concepts of Probability
Sample spaces, the long-run view of probability, and the places intuition about chance goes wrong.
Random Variables
Probability distributions and expected value, ending with the airline that deliberately sells more tickets than it has seats.
The Binomial Distribution
When the binomial applies, when it does not, and how to compute with it without reaching for a table.
More on the way
Units for the normal distribution, confidence intervals and hypothesis testing are still being built. In the meantime, those chapters are covered by the interactive activities.