# Chapter 17 - Probability Applications; The Mth/probability.. Sub-menu - Part 1; Factorials, Combinations, And Permutations - HP F2226A - 48GII Graphic Calculator User Manual

Graphing calculator.

Chapter 17
Probability Applications
In this Chapter we provide examples of applications of calculator's functions
to probability distributions.

### The MTH/PROBABILITY.. sub-menu - part 1

The MTH/PROBABILITY.. sub-menu is accessible through the keystroke
sequence „´.
With system flag 117 set to CHOOSE boxes, the
following list of MTH options is provided (see left-hand side figure below).
We have selected the PROBABILITY.. option (option 7), to show the following
functions (see right-hand side figure below):
In this section we discuss functions COMB, PERM, ! (factorial), RAND, and
RDZ.

### Factorials, combinations, and permutations

The factorial of an integer n is defined as: n! = n
definition, 0! = 1. Factorials are used in the calculation of the number of
permutations and combinations of objects.
permutations of r objects from a set of n distinct objects is
P
=
n
r
Also, the number of combinations of n objects taken r at a time is
n
n
(
r
n
(
n
1
)(
n
1
)...(
n
r
+
) 1
n
1
)(
n
2
)...(
n
r
r
!
(n-1)
(n-2)...3
2
For example, the number of
=
n
/( !
n
r
)!
) 1
n
!
r
( !
n
r
)!
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