Difference between revisions of "Documentation/How Tos/Calc: PERCENTRANK function"

Revision as of 07:51, 22 April 2008

PERCENTRANK

Returns the percentage rank of a number in a list of numbers.

Syntax:

PERCENTRANK(numberlist; number)

number is the number whose percentage rank is to be found within the unordered range or array of numbers numberlist.

PERCENTRANK internally assigns a rank to number, where 0 is the rank of the lowest number, 1 of the next lowest and so on. If number, is not in numberlist, it is assigned a fractional rank proportionately between the rank of the numbers on either side (see the examples). Where N is the count of numbers in numberlist, PERCENTRANK returns assigned_rank / (N-1), which is a fraction between 0 and 1 inclusive.

This function is of limited use with a small list of numbers. It may be useful for example when determining where a score lies within all scores for a test, in which case the formula returned can be stated as L / (N-1), where L is the count of numbers which are lower than number.

Example:

PERCENTRANK(A2:A99; A7)

where cells A2:A99 contain scores from a test, returns the percent rank (as a fraction) for the student whose test score is in cell A7.

The next two examples illustrate the calculation, but have little practical application:

PERCENTRANK({3; 4; 9; 11; 12}; 4)

returns 0.25.

PERCENTRANK({9; 3; 7; 8}; 6)

returns 0.25. The lowest number 3 is assigned rank 0; the next highest number 7 is assigned rank 1. 6 is assigned a rank proportionately between these, 0.75. There are 4 numbers in the list, so the result is calculated as 0.75/(4-1) = 0.75/3 = 0.25.

See also:

RANK, PERCENTILE

Statistical functions

Issues:

• Despite its name, PERCENTRANK returns a fraction, not a percentage.