Learning to calculate percentiles is very useful and important for almost anyone. It is necessary to learn to calculate percentiles to be able to do these calculations at any time in our lives in which we need to know how to get a percentile. To clarify the doubts about how to calculate percentiles and you can do the math yourself, here you can see some examples that will help you step by step so you can calculate percentiles.
Instructions for calculating percentiles
- You have to keep in mind that each percentile represents a unit of 1% of the total of 100. In other words, suppose you have 60 cookies, even if they are 60, since 60 is the total number of cookies, 60 is 100%. 100% is the total amount of data we have.
- We will divide this into 100 equal parts, so we can calculate the percentile we are looking for thanks to this divided data.
- The basic formula to calculate percentiles is the following: L /N :100 = P. The L represents the numbers smaller than the total data we have, N is the total data we have and 100 is the number we must divide it into to reach the percentile.
- As a first example to calculate percentiles, we are going to calculate a percentile, in this case it will be 50, which represents 50% of the data or equal parts of 100% of the cookies we have.
- To find the 50th percentile we will understand the following; Since 60 is 100% of our data and we want to find the 50th percentile, that is, 50% of our data, then we make the following equation: 60 x 50:100, that is, 60 times 50 out of 100.
- We will eliminate two zeros and we will be left with a count like this: 60 x 5:10. The result will be 30. So 30 cookies out of 60 is 50% of our data. The 50th percentile is the 30th data.
- Now another example of how to calculate percentiles. We have 70 people of which 30% have leprosy. 70 is 100 of our data and we want to get the 30th percentile. To calculate how many people have leprosy we will do the following equation: 70 x 30 :100.
- The result obtained is number 21, so 21 people out of 70 are sick with leprosy, so we can conclude that the 30th percentile is data 21.
- As a last example to help you understand how to calculate percentiles we will use the following situation; a girl is 18 years old, and she has practiced ballet for 14% of her life. We want to find the 14th percentile. Since 18 is 100% of her current age then we make the following equation: 18 x 14: 100 = 2.52. Which is why this girl has practiced ballet for a little over two and a half years of her life. However, when these figures are applied to money or only to numbers, it is advisable to round the result to the closest possible that is higher than the one obtained, in this case we will round to 3.
What do you need to calculate percentiles?
- Spreadsheet and pencil preferably.
Tips for Calculating Percentiles
- Help yourself with a spreadsheet to be able to calculate the percentile data faster.
- When a result is not complete, it is better to round the count to reach a higher number than if it is complete, never a lower number.