What is conditional probability?

Conditional probability is the probability of an event occurring given that another event has already occurred.

In a two-way table summarizing student grades and gender, what information do you use to calculate the probability of a student being male given they received a B?

You would use the number of male students who received a B and the total number of students who received a B.

The answer is the number of people in the 13-17 age group that prefer TikTok divided by the total number of people in the 13-17 age group.

Divide the number of seniors taking Spanish by the total number of seniors.

The probability is 1/6 or approximately 0.167.

I can calculate conditional probabilities using two-way tables.

1
Conditional probability is the probability of an event occurring, given that another event has already occurred.
2
To find the probability that a selected student would be female given they received an A on the test, you can divide the number of female students who received an A by the total number of students who received an A.
3
The formula for conditional probability is P(E₂|E₁) = P(E₂ and E₁) / P(E₁), where E₂ is the event we're interested in and E₁ is the given event.