Frequency diagram

Fre­quency di­a­grams, like wa­ter­fall di­a­grams, provide a way of vi­su­al­iz­ing Bayes’ Rule. For ex­am­ple, if 20% of the pa­tients in the screen­ing pa­tient are sick (red) and 80% are healthy (blue); and 90% of the sick pa­tients get pos­i­tive test re­sults; and 30% of the healthy pa­tients get pos­i­tive test re­sults, we could vi­su­al­ize the prob­a­bil­ities as pro­por­tions of a large pop­u­la­tion, as in the fol­low­ing fre­quency di­a­gram:

Frequency diagram

See Fre­quency di­a­grams: A first look at Bayes for a walk­through of the di­a­gram.

Children:

Parents:

  • Bayes' rule

    Bayes’ rule is the core the­o­rem of prob­a­bil­ity the­ory say­ing how to re­vise our be­liefs when we make a new ob­ser­va­tion.