posted on 03:38 PM on Thursday 20 April 2023
So there is South Korean grandmother who took 960 tries to get her driver's licence and has been given a World Record for it.
She took the theory test 950 times before passing. She needed to get 60 of 100 marks to pass the test which means quite a low bar.
But a quick calculation in R using the binomial distribution showed that the probabilities of getting more than 60 of 100 marks in a MCQ test with 4 options is very low, just 3.459551e-08. So grandma actually learnt something along the way.
A simulation of the test depicted as a density plot in R.
The probabilities are far lower than I expected :-)