# Chapter 15 - Probability Distributions; The Mth/probability.. Sub-menu - Part 1; Factorials, Combinations, And Permutations - HP 48gII User Manual

Graphing calculator.

Chapter 15
Probability Distributions
In this Chapter we provide examples of applications of the pre-defined
probability distributions in the calculator.

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

The MTH/PROBABILITY.. sub-menu is accessible through the keystroke
sequence „´.
following functions are available in the PROBABILITY.. menu:
In this section we discuss functions COMB, PERM, ! (factorial), and RAND.

### 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.
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
With system flag 117 set to CHOOSE boxes, the
For example, the number of permutations of r
+
n
(
n
1
)(
n
1
)...(
n
r
(
n
1
)(
n
2
)...(
n
r
r
!
(n-1)
(n-2)...3
=
) 1
n
/( !
n
r
)
+
) 1
n
!
=
r
( !
n
r
)!
2
1. By
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