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

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(Example:: added practical example)
(Syntax:: used r for rank)
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: <tt>'''number'''</tt> is the number whose percentage rank is to be found within the unordered range or array of numbers <tt>'''numberlist'''</tt>.
 
: <tt>'''number'''</tt> is the number whose percentage rank is to be found within the unordered range or array of numbers <tt>'''numberlist'''</tt>.
  
: <tt>'''PERCENTRANK'''</tt> internally assigns a rank to <tt>'''number'''</tt>, where 0 is the rank of the lowest number, 1 of the next lowest and so on. If <tt>'''number'''</tt>is not in <tt>'''numberlist'''</tt>, 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 <tt>'''numberlist'''</tt>, <tt>'''PERCENTRANK'''</tt> returns ''assigned_rank'' / (''N''-1), which is a fraction between 0 and 1 inclusive.
+
: <tt>'''PERCENTRANK'''</tt> internally assigns a rank ''r'' to <tt>'''number'''</tt>, where 0 is the rank of the lowest number, 1 of the next lowest and so on. If <tt>'''number'''</tt> is not in <tt>'''numberlist'''</tt>, 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 <tt>'''numberlist'''</tt>, <tt>'''PERCENTRANK'''</tt> returns ''r'' / (''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 <tt>'''number'''</tt>.
 
: 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 <tt>'''number'''</tt>.

Revision as of 18:15, 23 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 r 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 r / (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.
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