Guided practice
Case studies
Each case study works through one business question in steps: the data, a model, the numbers it gives, and what they do and do not say. Every step has a chart or a checked answer, and the answers you get right are kept in this browser.
Check a new batch of a vaccine: unsatisfactory doses among 10 and 20 as binomials, then the time a dose takes to work as a normal. 0 of 6 checks answered correctly.
Model a share's returns with the normal: a day, a year by the square root of time, and the fat tails the model misses. 0 of 3 checks answered correctly.
A year of daily book sales as a discrete uniform, the boundaries stated exactly, and a month's average by the central limit theorem. 0 of 3 checks answered correctly.
Model how long a bug takes to fix, set aside a model that looks plausible and is not, and budget a sprint with the central limit theorem. 0 of 3 checks answered correctly.
A supplier claims 5 % of its bulbs are faulty, and a test finds 4 in 20: binomial tails as the first step towards a hypothesis test. 0 of 3 checks answered correctly.