Conditional Probability · Bayes' Formula

Lesson 9

Nikolai Chukhin · Alexander S. Kulikov

Problem. You work in the banking department that analyzes “suspicious” transactions. You have a tool that helps detect such transactions, but it is not perfect:

  • If a transaction is indeed suspicious, the tool detects it and blocks the account with a probability of 75 percent.

  • If a transaction is normal, the tool mistakenly blocks the account with a probability of 5 percent.

It is known that the proportion of suspicious transactions among all transactions is 3 percent. What is the probability that a randomly blocked account is actually not associated with a suspicious transaction?

5 points