Of 755 drivers, 450 do not use a phone and 405 of those had no violation. What is the probability of no violation given no phone use?

1. The condition is not using a phone, so the sample space shrinks to those 450 drivers. 2. Of those 450, exactly 405 had no violation in the last year. 3. The conditional probability is therefore 405/450. 4. Using 685 as the denominator conditions on having no violation instead, which reverses the question. _Source: OpenStax Introductory Business Statistics (CC BY 4.0), Ch 3 "Probability Topics", section 3.4 Contingency Tables and Probability Trees_