Lesson 4 of 12Article18 min
Probability Foundations
P(A) is a number in [0,1] measuring long-run relative frequency (frequentist view) or coherent belief (Bayesian view). Both share the same algebra of events.
Rules of chance
P(A) is a number in [0,1] measuring long-run relative frequency (frequentist view) or coherent belief (Bayesian view). Both share the same algebra of events.
Worked Bayes sketch
Disease rate 1%, test 99% sensitive and 99% specific. P(disease|positive) is still only about 50% — base rates matter. Always write the tree or Bayes formula before trusting intuition.