Lets say I have a list of values 1 2 3 4 5 6 7 8 9 10.
and I want to find the 20percentile I whould do this.
20/100*10=2 position two which just happens to have the value of 2 thats fine.
Now lets say I have this list of values 1 2 3 4 5 6 7 8 9
and I want to find the 20 percentile I whould do this.
20/100*9=1.8 because this now produces a decimal do just round up to position two
which just happens to have the value of 2.
because if I find the average of the first ad secund value I get a decimal again ie 1.5.
Conclution: If theres an even number of values just take that value and if theres an odd
number of values round up and take that value?