Reverse the condition on Georgian Bay Mutual’s tree — P(auto | fraud) from the leaf over the total — and count the audit samples with math.comb.

Answer

import math p_auto_and_fraud = 0.60 * 0.10 p_fraud = p_auto_and_fraud + 0.40 * 0.04 print(f"P(auto|fraud)={p_auto_and_fraud / p_fraud:.4f}") print(f"C(10,3)={math.comb(10, 3)} C(50,2)={math.comb(50, 2)}")

IBS1 §3.4 (reversal implicit in the table method), §4.1 (combinations), CC BY 4.0 — shape only; Balka ch 4 (ordering); original dataset