How to Calculate Probability in Excel

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10 years ago

You probably want to know how to calculate probability with Excel. You’ll learn how to calculate probability in Excel using built-in functions like PROB, as well as how to handle more complex scenarios such as dice rolls, coin flips, and poker hands.

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PROB function in Excel

You can use the PROB function to calculate the probability in Excel. This function calculates the probability that values in a range fall within a specified range of values.

Syntax of the PROB Function:

PROB (range_x, sample_range, lower_limit, [upper_limit])

x_range: range of x values.
prob_range: range of x cells.
lower_limit: the lower limit of the probability value
upper_limit: The upper limit of the probability value is set here. This argument is optional.

The PROB function can be used to calculate the probability of values falling within any range, not just a fixed range.

Here are some examples of how to use the PROB function in Excel to calculate probability.

Simple probability example

Suppose you want to calculate the probability of a grade falling within a specific range.

Enter data in Excel sheet.

To calculate probability, use the PROB function.

The formula here is =PROB(A2:A10,B2:B10,B13,B14) where

A2:A10 is range of marks in this example
B2:B10 is a chance of getting the grade from A column
B13 is lower range
B14 stands for upper range

The probability here is 45%.

Calculating Probability for Two Dice Rolls

Let’s check what the probability is for rolling two dice.

I prepared data.

First, I need to calculate the chance of rolling the die.

When rolling two dice, the possible outcomes range from 2 to 12. Some sums occur more frequently than others (e.g., rolling a 7 is more likely than rolling a 2). The roll chance formula is: =COUNTIF($C$4:$H$9,K4)

I used absolute reference in the formula.

There are:

only one chance to roll 2 and 12
two chances to roll 3 and 11
three chances to roll 4 and 10
four chances to roll 5 and 9
five chances to roll 6 and 8
six chances to roll 7

To calculate the probability of 2 dice, you need to divide the number of chances by the sum of chances.

The probability formula for two dice is=$K4/SUM($K$4:$K$14)

Two dice probabilities are from 2.78% to 16.67%.

Based on the above calculations, you can easily calculate what the probability of rolling doubles is.

There are only six chances to do that, so the probability of rolling doubles is 6/36 = 16.67%. The interesting thing is that the probability of rolling doubles is exactly the same as rolling 7.

Calculating Coin Flip Probability

It is 50% to flip the head and 50% to flip the tail. Have you ever wondered what the probability is of flipping the head (or tail) 11 times in a row? Let’s calculate it in Excel.

First, let’s calculate the probability of flipping a head once. It is easy. 50%. head or flip.

By translating it to the Excel language, we can create an Excel formula: =POWER(0.5,1)

Further, the probability is equal to =POWER(0.5, number_of_tries).

The probability of flipping a head (or tail) 11 times in a row equals 0.04883%, which is less than 0.05%!

Flipping a head 10 times is 0.09766% probable.

Flipping your head (or tail) 20 times in a row is 0.000095% probable.

We can also look for the possibility of flipping heads (or tails) several times in a row. It’s easy because each time is 2 times less probable.

It’s 1: 2048 odds of flipping a head (or tail) 11 times in a row. It means that every 2048 times you flip a coin, 11 times you flip 11 heads (or tails).

Poker Probability Calculation

It will be fun to analyze the poker probabilities.

First, use the Excel function to check the number of poker combinations. There are 52 cards, from which you get only 5. From a mathematical point of view, it is a simple combination to be used. There is an Excel function COMBIN, for that. Functions take just two arguments as a combination. Simply use the Excel formula =COMBIN(52,5)

It turns out there are 2,598,960 combinations in poker.

To calculate the probability of getting a pair or two pairs, you need to calculate the number of combinations of getting them. And then just divide the two numbers.