How Many Quartiles Are There In A Series?

Team Careers360Updated on 27 Mar 2023, 12:43 PM IST

A quartile has 4 series represented by Q1, Q2, Q3 and Q4.

This is a term used in statistics. A quartile is used when a particular observation of data is divided into 4 equal parts to check the influence of each part of the data on the whole observation. Three points are used to divide the data into four identical portions. The use of this kind of statistical analysis helps in the development of box and whisker plots. Quartiles are, in fact, specific values or lines that divide the data into three quarters.

The middle point or line will be the centre point (median) of the data or distribution. The other two points or lines show half the median values (one upper-half quartile and one lower-half quartile). By observing a graph and a quartile, we can understand the dispersion of the data set.

Distribution

Any observation must be arranged in ascending order before finding the quartiles. Three quartiles divide the observation into four parts. The first quartile is represented by Q1, the second by Q2, and the third by Q3. Q2 represents the median position or average. The quartiles divide the whole representation in such a way that 25% of the data are present lesser than the lower quartile (Q1), 50% of the data are lesser than the mean value (Q2), 75 % of the data are lower than then higher quartile (Q3). The quartiles of data can be analysed by the following:

First Quartile(Q1) = ((n + 1)/4)th Term
Second Quartile(Q2) = ((n + 1)/2)th Term
Third Quartile(Q3) = (3(n + 1)/4)th Term

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Interquartile Range

This is 50% of the values present in the middle. This is represented by the data present between the upper quartile and the lower quartile. This is helpful because the analysis of interquartile data gives importance to the data set by avoiding outliers, which is the data that has gone too low or too high.