No 100th percentile?

Because there are only 100 percentiles and the "0th" percentile counts as #1.

I get the feeling that you won't be flirting with the 100th percentile so I guess this is more of a theoretical than a practical question.

Math Man wrote:

I get the feeling that you won't be flirting with the 100th percentile so I guess this is more of a theoretical than a practical question.

Well put.

You cant be neither a 0 or 100 percentile. Both are absolutes. Think of it as a room 100ft long, it is impossible to stand on the 0 ft line or the 100ft line.

The 100th percentile represents positive infinity. This wouldn't work with something like height or weight or IQ or whatever. There wouldn't be a 100th percentile, because you theoretically could grow/be infinitely tall/fat/smart/whatever. So in the case of a test where you can actually achieve a perfect score, wouldn't 25 out of 25 actually be 100th percentile?

JL Gunner wrote:

Well put.

You cant be neither a 0 or 100 percentile. Both are absolutes. Think of it as a room 100ft long, it is impossible to stand on the 0 ft line or the 100ft line.

But he got an absolutely perfect score. Not saying you're wrong. I'm just speculating here.

This was just on Suits on USA network last week. There is no 100th percentile (according to a network sitcom). because just like counting 0-1 is 1. 1-2 is 2, etc so 99-100 would be the 99th percentile...you can't go any higher bc that is the top 1%. Its a percentile rank not a 1-100 ranking.

A percentile is a comparison to others not a percentage, it tells you how many scored below a given level. The scale has an asmyptote at 100, you can get really close, but can't quite get there. Even if you had the top score and that score was perfect you didn't do better than yourself. Sometimes percentiles are calculated with how many scored at or below a certain level, but even then you have to account for the fact that there could be more than one perfect score so you still couldn't be in the 100th percentile. The more people in the pool the closer to 100 the top person would be.

Percentiles probably wouldn't even be used for a class of 25 people unless it was a class that had been taught many times and had many 100's of students past and present for comparison.

Look at something like the ACT where 1000's of people take it every year. Even if you got a perfect score there is probably at least one other person out there who did the same thing and you can't say that did better than them.

awesomeness... wrote:

0-1 is 1. 1-2 is 2, etc so 99-100 would be the 99th percentile...

I was thinking this too, but if 0-1 is 1 and 1-2 is 2 then 99-100 would be 100.

To the poster that siad there was no 0th percentile either that is not correct. The percentile is a 100 point scale based on how many people, or items, or test scores etc. are below a certain level. Someone is at the bottom and in the 0th percentile.

The common sense easy-to-understand definition of percentile is what percent of people you EXCEED.

Since you can't exceed yourself, you can never be 100th percentile.

And if you score the best out of 25 people, you aren't even 99th percentile.

Nah, there is a 100th percentile. It depends on how you define your population. If it is how students perform in a class, the top student is the 100th percentile. If you are instead describing the entire possible population of students, then it is an infinite population and you cannot have a 100th percentile.

Thanks! This helped significantly!

Any other explanations would still be great...

Sambouie wrote:

The common sense easy-to-understand definition of percentile is what percent of people you EXCEED.

Since you can't exceed yourself, you can never be 100th percentile.

And if you score the best out of 25 people, you aren't even 99th percentile.

This should have ended the thread.

You were in the 96th percentile. You can view the percentile as the percentage of people you beat. If you were 1 out of 100 you would be in the 99th percentile, 1 out of 1,000 and your in the 99.9 percentile.

You can never say you are in the 100 percentile unless there were infinity people taking the exam, which would be impossible.

Ha I thought of suits too when I saw this

Yeah, that all clears it up for me. THANKS, BROS.

If you had the best score out of 25 people then you did better than 96% percent of the total population (including yourself). You are in the 96th percentile.

If you had the top score out of 1000 then you did better than 99.9%.

You are IN the 99th percentile.

You just can't hit 100%. But you can round to it.

If you can't figure this out on your own, then I doubt you are in the 100th percentile of anything (which, regardless, is impossible).

Think of it as the "TOP 96%"

This descriptive increment is used in things like Terra Nova testing for grade school kids to find out where they rank throughout the country. To use it in a class of 25 defeats the purpose of it because it adds 4x as many counters as off 25 students. (I was all excited as a child being ranked in the top 98 percent in Math for this testing.)

They are putting you at 96% because you are 96%+ meaning that when you are in the range of 96-100%. Since there are 25 people in your class, that is (like I said before) 4x less than 100.

100/25= 4

100-4= 96

You will RANGE anywhere from 96-100.

That is all.

But, look here:

If 0 to 1 is the first percentile, and 8 to 9 is the ninth percentile, then 9 to 10 IS the tenth percentile.

Accordingly-- 99 to 100 is the one hundredth percentile.

My SAT results in 1976 said that I scored in the 98th percentile of all college-bound seniors, and in the 100th percentile of all test takers nationwide.

So, just to say-- yeah, there's a 100th percentile.

Percentiles represent actual values, not ranges. Just because you receive a letter in the mail that says you scored in the 100th percentile doesn't make it correct.

It is also important to remember that percentiles are not meant to be used in data groups less than 100, they are a way of efficiently looking at LARGE groups of data.

Take an example of a test where 101 different students score 0, 1, 2, 3, 4, 5, 6, 7, 8, 9... all the way to 98, 99, and 100 points respectively.

The student who scored the 0 scored higher than 0% of the group, he is at the very bottom, the 0th percentile. Students below him = 0, total students = 101. 0/101 = 0%.

The student who scored the 1 scored higher than 0.99% of the group, he is in the 9.09th percentile. Students below him = 1, total students = 11. 1/101 = 0.99%

The student who scored the 2 scored higher than 1.98% of the group, he is in the 18.18th percentile. Students below him = 2, total students = 11. 2/101 = 1.98%

This continues on, let's skip to the student who scored the 99. Students below him = 99, total students = 101. 99/101 = 98.02% He is in the 98.02nd percentile.

Here comes the fun one, the student who scored the 100. Students below him = 100, total students = 101. 100/101 = 99.009%. He is in the 99.009th percentile.

By increasing the population of data, you can increase the denominator to very large numbers, but the highest the numerator can EVER reach is the denominator -1, because a value can never be higher than itself. You can have someone score higher than 9,999,999 other people, but because they are taking the exam as well, the total number of scores is out of 10,000,000. 9,999,999/10,000,000 = 99.99999% but it can NEVER reach 100% There is no such thing as the 100th percentile.