Question

In a class of students, the following data table summarizes how many students have a cat or a dog. What is the probability that a student who has a cat also has a dog?
Has a cat Does not have a cat
Has a dog 9 10
Does not have a dog 6 4

Answer 1

We want P(has dog | has cat) = (number with both) / (number with cat) = 9 / (9+6) = 9/15 = 3/5 = 0.6 (60%).