PRECENTILE
The ninety nine points on the scale of observation s( or values of the variable) which divide the total frequency into hundred equal parts are called percentiles for the data arranged in ascending or descending order of magnitude..
When data are in ascending order the first is called first percentile and is denoted by P_{1} the second point is called second percentage and is denoted by P_{2} and so the last point is called ninety ninth percentile and is denoted by P_{99}.