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 2 3
Does not have a dog 14 10
Answer

1 answer

To find the probability that a student who has a cat also has a dog, we need to first identify the relevant counts from the data table provided:

  • Students who have both a cat and a dog: 2
  • Students who have a cat but do not have a dog: 14

Now, we can sum these two numbers to find the total number of students who have a cat:

\[ \text{Total students with a cat} = \text{(Students with a cat and a dog)} + \text{(Students with a cat and without a dog)} = 2 + 14 = 16 \]

The probability that a student who has a cat also has a dog can be calculated using the formula:

\[ P(\text{Has a dog} \mid \text{Has a cat}) = \frac{\text{Number of students with a cat and a dog}}{\text{Total number of students with a cat}} \]

So we have:

\[ P(\text{Has a dog} \mid \text{Has a cat}) = \frac{2}{16} = \frac{1}{8} \]

Thus, the probability that a student who has a cat also has a dog is \(\frac{1}{8}\).