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how to find percentiles

find the 75th and 90th percentiles for the data 0-100

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Zoltan B. | Researcher whose work has been presented at Ivy League venuesResearcher whose work has been presented...
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Calculate percentiles can tell us how numbers are distributed.

Assume eight numbers: [0, 2, 4, 6, 8, 10, 12, 14]

Notice that these 8 numbers are arranged from lowest to highest: That's how you need to arrange your numbers to calculate percentiles. If the numbers are not arranged lowest to highest, make sure you order them this way. This is important because a percentile tells you how well you did compared to others and that comparison needs to be organized.

Let N equal the number of data points. Here N=8.

The formula is P=(k/100)(n).

K is the percentile you want to find. Here that's 75


P is the position in the distribution that corresponds to the 75th percentile. Here, it's the data point in the 6th position.

The data set is [0, 2, 4, 6, 8, 10, 12, 14]

10 is in the 6th position. Therefore, the 75th percentile of this data set is 10.