Flashcards
exam p distributions
Cards in this deck (12)
- 1Discrete UniformEqual probability of each outcome
X ~ DUnif(a,b)
f(x) = 1 / (b-a+1)
E[X] = (a+b) / 2
VAR[X] = (b-a+1)^2 - 1 / 12 - 2Binomialbin(n,p)
to # count successes of n independent trials with constant success probability p and binary outcomes for each trial
- 3hypergeometricf(x) above is for two categories
hypgeom(M,N,n)
to count # successes of n dependent trials with P(success) not constant across the trials (sampling w/o replacement)
- 4geometricgeom(p)
to count # independent bernoulli trials required to get 1 success where each trial has p = P(success)
- 5negative binomialnegbin(r,p)
how many independent bernoulli trials until r successes
- 6poissonpois(lambda)
to count # occurrences of an event in a fixed interval
- 7continuous uniformeg. a bus arrives at a bus stop uniformly
- 8exponentialexp(theta=1/lambda)
to model waiting time between independent events that occur with a constant average rate (lambda)
- 9gammagamma(alpha,beta)
to model waiting until next alpha occurrences of an event
- 10normalnorm(mu, sigma2)
standard normal rv Z ~ norm(0,1)
- 11lognormalX ~ lognorm <=> ln(X) ~ norm
Y ~ norm <=> e^Y ~ lognorm
- 12betabeta(alpha beta)
to model probabilities
Information
- Description
- pmfs,pdfs, expected values, variances, special properties
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- Nguyen Tran
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