I am trying to calculate quantile for a column values manually, but not able to find the correct quantile value manually using the formula when compared to result output from Pandas. I looked around for different solutions, but did not find the right answer
In [54]: df
Out[54]:
data1 data2 key1 key2
0 -0.204708 1.393406 a one
1 0.478943 0.092908 a two
2 1.965781 1.246435 a one
In [55]: grouped = df.groupby('key1')
In [56]: grouped['data1'].quantile(0.9)
Out[56]:
key1
a 1.668413
using the formula to find it manually,n is 3 as there are 3 values in data1 column
quantile(n+1)
applying the values of df1 column
=0.9(n+1)
=0.9(4)
= 3.6
so 3.6th position is 1.965781, so how does pandas gives 1.668413 ?