Probability Functions - HP -32S Owner's Manual

Probability Functions
The PROB (probability) menu has functions to calculate factorials,
combinations, and permutations, and to obtain random numbers.
The PROB Menu
Menu Label
{Cn,r}
{Pn,r}
{*!}
{R}
Description
Combinations. Enter n first, then r. (Nonnegative integers
only.) Calculates the number of possible sets of n items
taken r at a time. No item occurs more than once in a set,
and different orders of the same r items are not counted
separately.
Permutations. Enter n first, then r. (Nonnegative integers
only.) Calculates the number of possible arrangements of n
items taken r at a time. No item occurs more than once in
an arrangement, and different orders of the same r items
are counted separately.
Factorial and Gamma. Calculates the factorial of the dis
played positive integer (0 «s x < 253).
To calculate the gamma function of a, T(a), key in (a - 1)
and pressBIprobI {*! }. (The {x! } function calcu
lates T(x + 1). The value for x cannot be a negative
integer.)
Random number generator. Has two options.
Pressing {RANDOM} generates a random number in the
range 0 < x < 1.* Pressing {SEED} starts a new ran
dom-number sequence with the number that is in the X-
register.
The random number generator in the HP-32S actually returns a number that is part of a
uniformly distributed pseudo-random number sequence. It passes the spectral test (D.
Knuth, Seminumerical Algorithms, vol. 2. London: Addison Wesley, 1981).
{RANDOM} uses a seed to generate a random number. Each random
number generated becomes the seed for the next random number.
Therefore, a sequence ofrandom numbers can be repeated by starting
with the sameseed. You can store a new seed with the {SEED} func
tion. If memory is cleared, the seed is reset to zero.
4: Real-Number Functions 65