Looking for ways to calculate conditional probability in Excel? Then, this is the right place for you. Here, you will find 2 easy ways to calculate conditional probability in Excel.
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What Is Probability?
Probability is the mathematical representation of how often an event can occur. It is a number between 0 to 1. 0 means that an event is not going to happen and 1 represents that event is certainly going to occur.
What Is Conditional Probability?
Conditional probability is used to calculate the probability of an event (second), depending on whether another one or more events (first) have already occurred.
Suppose, A & B are two events that can occur.
Now, if the Probability of A = P(A), the Probability of B =P(B) and the Probability of both A & B = P(A∩B)
Then, the formula of Probability of B, if A event has already occurred,
P(B|A) = P(A∩B) / P(A)
2 Easy Ways to Calculate Conditional Probability in Excel
We can calculate the conditional probability for both one-way and two-way tables in Excel. Here, you will find these two ways of calculation going through some simple steps given below.
1. Calculate Conditional Probability for One-Way Table
In the first method, we will show you how you can calculate the conditional probability for a one-way table. Here, we have a dataset containing the probability of ordering Food, Books and both at a time. Now, using this dataset we will show you how you can calculate the probability of people who ordered books after conditioning that they have ordered food.
Here are the steps.
- In the beginning, select Cell C8 and insert the following formula.
- Then, press Enter to get the value of Conditional Probability.
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2. Determine Conditional Probability for Two-Way Table
In the second method, you will find a way to determine the conditional probability for a two-way table.
Suppose, you have a dataset containing information about the number of Boys and Girls who play either Football or Baseball or both. Now, we will show you the way to calculate the probability of choosing a Boy who also plays Football using the given dataset.
- Firstly, select Cell E9 and insert the following formula.
- Secondly, press Enter to get the Probability of choosing a Boy, P(B).
- Then, select Cell E10 and insert the following formula.
- Now, press Enter.
- After that, select Cell E11 and insert the following formula.
- Finally, press Enter to get the value of your desired conditional probability.
Conditional Probability for Independent Events in Excel
When two events are independent it means that they do not affect the probability of each other. Suppose, A & B are two independent events.
As a result,
P(A|B) = P(A) and P(B|A) = P(B)
Conditional Probability for Mutually Exclusive Events in Excel
Mutually Exclusive Events means events that cannot happen at the same time. For example, raining and not raining on a day can be two mutually exclusive events. If the probability of raining is P(R) and not raining is P(NR) then,
P(R|NR) = 0 and P(NR|R) = 0
In the article, you will find an Excel workbook like the image given below to practice on your own.
So, in this article, we have shown you 2 ways to calculate conditional probability in Excel. I hope you found this article interesting and helpful. If something seems difficult to understand, please leave a comment. Please let us know if there are any more alternatives that we may have missed. And, visit ExcelDemy for many more articles like this. Thank you!
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