# Deciles and Percentiles

__Deciles__:

The deciles are the partition values which divides the set of observations into tem equal parts. There are nine deciles namely . The first decile is is a point which has 10% of the observations below it.

__Deciles for Individual Observations__ (Ungrouped Data):

__Quartile for a Frequency Distribution__ (Discrete Data):

__Quartile for Grouped Frequency Distribution__:

__Percentiles__:

The percentiles are the points which divide the set of observations into one hundred equal parts. These points are denoted by , and are called the first, second, third, …, ninety ninth percentiles. The percentiles are calculated for very large number of observations like workers in factories and the population in provinces or countries. The percentiles are usually calculated for grouped data. The first percentile denoted by is calculated as . We find the group in which the itemlies and then is interpolated from the formula.