Description Computes the number of combinations possible by taking k items at a time from a pool of n, when order in the sample taken is not important.
Syntax COMBIN ( number, chosen)
| Argument | Description |
|---|---|
| number | A positive integer representing the total number of items in the pool of items. Decimal numbers are rounded down to the next-lower integer. Text in the argument list is interpreted as numeric, if possible; otherwise, the function returns the #NAME? error. Logical values in the argument list are interpreted as 1 for TRUE and 0 for FALSE. Text and logical values in range references return the #VALUE! error. |
| chosen | A positive integer representing the number of items taken from the pool at a time. It must be less than number. Decimal values are rounded down to the next-lower integer.Text in the argument list is interpreted as numeric, if possible; otherwise, the function returns the #NAME? error. Logical values in the argument list are interpreted as 1 for TRUE and 0 for FALSE. Text and logical values in range references return the #VALUE! error. |
Remarks For an example of the use of this function, say we have a box containing four different items. The number of combinations possible taking out 2 items at a time is 6; that is, the six combinations of items 1-2, 1-3, 1-4, 2-3, 2-4, and 3-4.
This function is similar to the PERMUT function, except that PERMUT requires the samples to be ordered, while COMBIN takes samples in any order.
Equation
where n is the total number of items and k is the number of items taken at a time.
Examples This function returns 6:
COMBIN(4,2)
This function returns 252:
