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