How do you calculate a percentile?

Question

is there a formula? do I make a proportion? what goes in the proportion? thanks for your help.

Answer 1

it depends on what kind of data you are talking about. for example, if you graduated 100th out of 250 people in your class, you would divide 100 by 250 (100/250) and you get 0.4. Subtract that from 1 and you get 0.60, or the 60 percentile - meaning you did better than 60% of the people in your graduating class.

if you are talking about a percentile rank in a normal distribution, this is probably too much labor to calculate by hand. lots of programs can do it for you. for example, in excel it is the =normdist function, you have to input a mean, and a standard deviation...

with slope (or line of best fit), it is also too laborious to complete by hand, but again many programs can calculate it. in excel, it is the =linest function, and you have to define all the points and constants. for the regression equation formulas see the website belong.

correlation is the statistical relationship between two variables; it describes the strength and relationship of the two variables. causation refers to cause and effect; smoking causes lung cancer. you usually heard the two paired in the phrase, "correlation does not imply causation," meaning, just because two things are related, does not mean one causes the other. for example, you could say height and weight are correlated; odds are, the taller you are, the more you weigh. but it will be silly to say that putting on a few pounds causes you to become taller.

i pray for you.

Answer 2

A percentile is nothing more than the value of a variable below which a certain percent of observations fall. So the 20th percentile is the value (or score) below which 20 percent of the observations may be found. For example: if you plot the IQs of people, 100 would be the 50th percentile. If 90% of people had an IQ less than 125, then you would say that people in the 10th percentile had an IQ of 125 or greater. That's all it means.