# Percentile calculation

If we consider the data items of 25 numbers and say for some reason we are only interested in the top 1% of the values or in other words we say 99 percentile how we would we apply the formula

L§= p(n+1)/100
L(90)=90/100 (*26)= 25.74

Since there are 25 values how do we calculate?

Also we hear the term people saying that they have scored 100 percentile. Which value would it correspond to?

Hi @rajiikm,
Yes, there are instances where we care about 99 percentile scores, but note that the sample size here (25) is just too small.
There’s no chance we can get a meaning out of 99 percentile here.

So how does the no of data points relate to percentiles. There was not any reference to it in the lecture. Will it be discussed later. Or can you throw more light on it

No, there’s no such reference, just wanted to convey that percentiles in real examples are used for large samples, example university students etc. and it makes sense to do a computation like 99 percentile there.
For small samples, round figure percentiles are used generally.

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Thanks for the clarification