Percentiles

Let the data be [4000, 500, 6000, 7000, 7500, 8000, 10000000] ; length of this data is 7

25th Percentile

Rank = (Percentile / 100) x (number of items + 1)

=> 25 / 100 * (7 + 1) = 2

So the 2nd value in the data is the 25th percentile.

Median is the 50th Percentile. To the left and right of median there are half of the data.

Rank = (Percentile / 100) x (number of items + 1)

=> 75 / 100 * (7 + 1) = 6

So the 6th value in the data is the 75th percentile.

The range between 25th and 75th percentile is called Interquartile Range

Last value in the dataset. Its the 100% or final value in the data.

df.<col_name>.quartile()

If you pass 0, then it is 0th Percentile, if you pass 1, then it is 100th Percentile, likewise 0.25 for 25th, 0.5 for 50th, and 0.75 for 75th.