Statistics,
made visible.
The normal distribution
Move a cutoff. See how the area under a curve becomes a probability.
Confidence intervals: z
Connect sample size and confidence with the precision of an estimate.
Confidence intervals: t
Explore the extra uncertainty when the population spread is unknown.
New to statistics? Begin with questions, data, and sampling →
Modules
13 modules · 17 lessons
The foundations 01–04
01Data & statistical thinking
Define a statistical question, identify variables, and see how sampling bias affects an answer.
02Describing data
03Probability
Connect events, conditional probability, independence, and Bayes’ rule.
04Probability distributions
Model counts with binomial and Poisson distributions, then explore a continuous normal curve.
Learning from samples 05–09
05Sampling distributions
Simulate repeated samples and connect sample size, standard error, and the central limit theorem.
06Confidence intervals
Understand how sample size, variability, and confidence affect precision.
07Determining sample size
Plan how many observations you need for a target margin of error, using a known population spread or a pilot sample.
08Hypothesis testing
Test a claim, interpret a p-value, and distinguish statistical evidence from practical importance.
09Comparing two groups
Compare independent means, paired observations, and two population proportions.
Making connections 10–13
10Categorical data
Read a contingency table and compare observed counts with independence.
11Correlation & regression
12Analysis of variance
Compare several means by separating between-group and within-group variation.
13Resampling & simulation
Construct bootstrap intervals and investigate group differences with a permutation test.
Follow the sequence or open the topic you need. Interactive examples, worked explanations, and practice at your own pace.