PSY 330 Human Factors
5/1/00
Day 2-18
Calculation of Human Error Probability - 2
uTHERP (Cont.)
uIn the diagram, a capital letter is a correct outcome and a small letter is an erroneous action.
uThe | symbol indicates a conditional probability.
uApply to starting a car.
lK = correct key
lk = incorrect key
lS = getting key into ignition
ls = missing ignition
lP(S|K) is probability of getting key into ignition, given getting correct key. This is the only correct outcome.
lP(error) = 1-P(S|K)