Quartile deviation

A practical measure of dispersion
Statistics is a very practical field. After all, what would we know from economic publications if it wasn’t for the preparation of statistics? The bigger, the better. The quartile deviation is one such practical measure. It belongs to the dispersion tool analysis – here, we are talking about the range of similarity between the studied objects and the average value.

To calculate the quartile deviation, we will need to know the values of the quartiles. They divide the population into four parts. Most methods of calculating quartiles in the population are based on the determination of the median. Obviously, medians and quartiles should be counted in an ordered series. To get the value of the quarter deviation, we calculate the value of the first and third quartiles.

Half of a half
The term from which the quartile deviation is derived is the quartile range otherwise known as the quartile spread. It is equal to the difference between the upper and lower quartiles. Exactly half of the surveyed objects fall within its range. Conversely, quartile deviation is exactly half of this range. It follows from the essence of the quartile deviation in which extreme values are not taken into account. The practical application of this measure is superior to that of the standard deviation in providing more detailed information about the variation of average results.

Undeniably, the practical application of the quartile deviation has its limitations, but which measure doesn’t have them? However, it is a very useful tool as it tells us a lot about the population and its variation.