Quartile Formula – First Quartile, Third Quartile & Lower Quartile Formula


Quartile Formula

Quartiles are given as values dividing the complete list into quarters. It will put the complete list of numbers in an order. It will cut the list into four equal parts. The other name for quartile is basically cuts. Further, they could be given as the upper quartile or the lower quartile.

The upper quartile is defined as the median of the upper half of a dataset. It is located by diving the data set with median and diving the upper half that could be considered as the median again. The median of upper half would be upper quartile and it can be given by formula as mentioned below –

first Quartile Formula

\[\large Q_{1}=\left(\frac{n+1}{4}\right)^{th}Term\]

second quartile Formula

\[\large Q_{2}=\left(\frac{n+1}{2}\right)^{th}Term\]

third Quartile Formula

\[\large Q_{3}=\left(\frac{3(n+1)}{4}\right)^{th}Term\]

Lower Quartile Formula

\[\large IQR=Upper\;Quartile-Lower\;Quartile\]

To make the things easy to understand, here we are giving upper quartile as Q3 or we can call it as upper quartile too. However, the value will not be for third quarter bit term number would be Q3. Here, N is representing the total number of elements within a dataset. Take an example, if there are total 9 elements in a dataset then the value of n would be nine in that case.

Hence, you just put the values into Quartile formula as find the final output as needed. In a few cases, when the final output is not a whole number then subtract .25 from the same and follow the earlier process as given.The quartile formula can be used for many real-world examples. For example, if you wanted to know how good a tutor is then we could apply quartile formula there.


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