# Video: Calculating a Conditional Probability from a Two-Way Frequency Table

Bethani Gasparine

The two-way table shows the ages and activity choices of a group of participants at a summer camp. A child is selected at random. Given that they chose abseiling, find the probability that the child is over 14.

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### Video Transcript

The two way table shows the ages and activity choices of a group of participants at a summer camp. A child is selected at random. Given that they chose abseiling, find the probability that the child is over 14.

Letβs go ahead and let event π΄ be to choose abseiling and event π΅ to be a child over 14. So it says, itβs given that they chose abseiling. Find the probability that the child is over 14. So we wanna know the probability of π΅, given that π΄ happened.

And the formula for the probability of π΅ given π΄ is: the probability of π΄ and π΅ divided by the probability of π΄. So the probability of π΄ and π΅, so choosing abseiling and being over 14 would be 24. Now the probability of π΄, so just of abseiling, how many people chose abseiling? Well, that would be 24 plus eight, so 32 total.

24 divided by 32 is 0.75 which would be 75 percent.