HP 33s Factorial, Gamma, Probability, Probability Functions, |i, 4–14, Seed, Combinations, Permutations, Random number generator, 4–14 Real–NumberFunctions

Probability Functions

Factorial

To calculate the factorial of a displayed non-negative integer x (0 ≤ x ≤ 253), press

{(the left–shifted key).

Gamma

To calculate the gamma function of a noninteger x, Γ(x), key in (x – 1) and press

{. The x! function calculates Γ(x + 1). The value for x cannot be a negative integer.

Probability

Combinations

To calculate the number of possible sets of n items taken r at a time, enter n first, {\, then r (nonnegative integers only). No item occurs more than once in a set, and different orders of the same r items are not counted separately.

Permutations

To calculate the number of possible arrangements of n items taken r at a time, enter n first, {_, then r (nonnegative integers only). No item occurs more than once in an arrangement, and different orders of the same r items are counted separately.

Seed

To store the number in x as a new seed for the random number generator, press

i.Random number generator

To generate a random number in the range 0 ≤ x < 1, press k. (The number is part of a uniformly–distributed pseudo–random number sequence. It passes the spectral test of D. Knuth, The Art of Computer Programming, vol. 2, Seminumerical Algorithms, London: Addison Wesley, 1981.)

4–14Real–Number Functions