Statistics

Statistics is the discipline of drawing conclusions from data when chance is involved, and of saying how confident you can be. A key idea is that a sample is just one possible draw, so any number you compute from it, like an average or a conversion rate, would wobble if you repeated the experiment. Tools like confidence intervals and p-values put a size on that wobble. They are easy to misread: a 95% confidence interval means the method captures the true value in 95% of repeated experiments, not that this particular interval has a 95% chance. Common traps include checking an A/B test repeatedly and stopping as soon as it looks significant, which inflates false positives.