Binomial & Geometric Distribution

Classify BINS

B = binary; each trial results in either a success or failure

I = independent; the trials are independent, so we can sample w/ replacement

N = number of fixed trials

S = success; probability of success on each trial is constant

when do u use binomcdf

binomcdf is used when you want the probability of getting at most a certain number of successes (like 0, 1, 2, up to x successes) across a set number of independent trials

when do u use binompdf

when u want the probability of exactly one number of successes in a fixed number of independent trials

classify BITS

B = binary; each trial results in either a success or failure

I = independent; the trials are independent, so we can sample w/ replacement

T - trials until success

S = success; probability of success on each trial is constant

when do you use geometcdf

when you want the probability of getting your first success before a certain trial

when do you use a geometpdf

when you want the probability that your first success happens exactly on a certain trial

for binomial, where do u put n, p, k in the thing

in this order (n = __, p = __, k = __)

for geometric, where do you put p and x

p goes first, x follows suit

if you have a geometric distribution that is P(x < k), what’s the easiest thing to do?

geometcdf (p, k-1)

if you have a geometric distribution that is P(x >= k), what’s the easiest thing to do?

1-geometcdf (p, k-1)