With the following scores: 80 32 69 50 92 59 75 66 88 67 37 66 98 90 90 81 Find a. P40

Question

May I know the formula and steps to calculate the question above?

Answer 1

First you need to put the numbers in order from smallest to largest.

Then you will find the slot number corresponding to the percentile as follows;

slot number = percentile in decimal * (number of slots + 1)

if slot number = whole number, then percentile is value in that slot number

If slot number != whole number (like 6.5), then percentile is average of values in slot numbers below and above computed slot number (6 and 7).

percentile in decimal, e.g., P40, would be 0.4. number of slots (n) = 16, number of slots + 1 = 17

slot number = 0.4 * 17 = 6.8

P40 will equal the average of the values in the 6th and 7th slots.