percentile?

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Could anyone please explain me the meaning of 'percentile' and how it's used? I've just seen some definitions but still I didn't get the point.
Regular Member695
You probably found that word in Statistics of a class when calculating exam results .It is a value on a scale of one hundred that indicates the percent of a distribution that is equal to or below it.

For example:

a percentile score of 80 is a score equal to 80 or better than 80% of the scores obtained.
Regular Member549
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I believe it refers to statictics. If you consider how a collection of values or samples distributes over the whole spectrum/scale, you can divide up this whole set of values into equally sized subsets ; say from the 10% lowest values to the 10% highest values. The 10% percentile is the value that has 10% of the sampled population below it (smaller than). The 90% percentile is the value that has 90% of the sample population below it (smaller than this value).
Not sure I've done such a good job of stating it clearly... Does it help in any way ?
Regular Member568
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Arrgh... Once again Savvy beat me to it... I just feel useless... Snif...
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Thank you both Emotion: smile you're extremely useful but I still have a question:

So you actually say that the a 80-th percentile is all the people who scored 80 or less. For instance, the 2-th percentile is the group of those who scored 1% or 2%? Is there any chance I got it right?
Maverick88Thank you both Emotion: smile you're extremely useful but I still have a question:

So you actually say that the a 80-th percentile is all the people who scored 80 or less. For instance, the 2-th percentile is the group of those who scored 1% or 2%? Is there any chance I got it right?

No, the percentile is for people who scored 80 or more.Similary, those who scored 2%.

___

If you don't mind I would like to add one more thing which has nothing to do with your original question.

Only objects are useful. When referring to people, it is an offending statement which gives a different context altogether.But I understand what you wanted to say. It should be ''you're extremely helpful''.

Regards.
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OK got it thanks Emotion: smile

P.S. Yes, I'm sorry (you got right what I meant) Emotion: smile

Thanks again!
Mav,
Actually I'm not sure what you mean by 'to score 80'. If this is the variable that you are statistically studying and sampling that has this value of 80 (whatever it is) then no, it doesn't quite work like you suggest.
The 80% percentile is the exact value that has 80% of the sampled population below it and 20% of the population above it.
Let's assume for argument's sake you study how tall are people in say Israel. For boys you may find the average height is 1.75 meters. You may also come to the conclusion for instance that the value of say 1.80 meters represents the 80% percentile, meaning that 80% of the boys are less than 1.80 meters tall.
Hope this clears it up a bit with the example.
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Hello Maverick,

I just came across this link: http://water.usgs.gov/waterwatch/percentile.html

Hope that steers clear of all your doubts.

Savvy
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