ApasScript.

Probability Distributions

binomialPmf

Binomial distribution: probability of exactly this outcome. Exact when p is exact. With an exact p, works up to n = 3000.

binomialCdf

Binomial distribution: cumulative probability P(X <= x). Exact when p is exact. With an exact p, works while n^2 * d is at most 230000, where d is the length of p's denominator (1 for 1/2 or 0.3, 3 for 0.123): n = 479 for p = 1/2, n = 276 for p = 0.123.

binomialMean

Binomial distribution: mean. Exact when p is exact.

binomialVariance

Binomial distribution: variance. Exact when p is exact.

normalPdf

Normal distribution: probability density at x.

normalCdf

Normal distribution: cumulative probability P(X <= x).

normalProb

Normal distribution: probability P(a <= X <= b).

normalQuantile

Normal distribution: the value x with P(X <= x) = p (inverse CDF).

poissonPmf

Poisson distribution: probability of exactly this outcome.

poissonCdf

Poisson distribution: cumulative probability P(X <= x). Works up to k = 30000.

poissonMean

Poisson distribution: mean.

poissonVariance

Poisson distribution: variance.

uniformPdf

Continuous uniform distribution: probability density at x.

uniformCdf

Continuous uniform distribution: cumulative probability P(X <= x).

uniformQuantile

Continuous uniform distribution: the value x with P(X <= x) = p (inverse CDF).

uniformMean

Continuous uniform distribution: mean.

uniformVariance

Continuous uniform distribution: variance.

exponentialPdf

Exponential distribution: probability density at x.

exponentialCdf

Exponential distribution: cumulative probability P(X <= x).

exponentialSf

Exponential distribution: survival probability P(X > x).

exponentialQuantile

Exponential distribution: the value x with P(X <= x) = p (inverse CDF).

exponentialMean

Exponential distribution: mean.

exponentialVariance

Exponential distribution: variance.

gammaPdf

Gamma distribution: probability density at x.

gammaCdf

Gamma distribution: cumulative probability P(X <= x).

gammaQuantile

Gamma distribution: the value x with P(X <= x) = p (inverse CDF).

gammaMean

Gamma distribution: mean.

gammaVariance

Gamma distribution: variance.

betaPdf

Beta distribution: probability density at x.

betaCdf

Beta distribution: cumulative probability P(X <= x).

betaQuantile

Beta distribution: the value x with P(X <= x) = p (inverse CDF).

betaMean

Beta distribution: mean.

betaVariance

Beta distribution: variance.

chiSquarePdf

Chi-square distribution: probability density at x.

chiSquareCdf

Chi-square distribution: cumulative probability P(X <= x).

chiSquareQuantile

Chi-square distribution: the value x with P(X <= x) = p (inverse CDF).

chiSquareSf

Chi-square distribution: survival probability P(X > x), the upper tail worked directly (accurate far into the tail).

chiSquareMean

Chi-square distribution: mean.

chiSquareVariance

Chi-square distribution: variance.

lognormalPdf

Lognormal distribution: probability density at x.

lognormalCdf

Lognormal distribution: cumulative probability P(X <= x).

lognormalQuantile

Lognormal distribution: the value x with P(X <= x) = p (inverse CDF).

lognormalSf

Lognormal distribution: survival probability P(X > x), through the normal upper tail.

lognormalMean

Lognormal distribution: mean.

lognormalVariance

Lognormal distribution: variance.

studentTPdf

Student's t distribution: probability density at x.

studentTCdf

Student's t distribution: cumulative probability P(X <= x).

studentTQuantile

Student's t distribution: the value x with P(X <= x) = p (inverse CDF).

studentTSf

Student-t distribution: survival probability P(T > t), the upper tail worked directly (accurate far into the tail).

studentTMean

Student's t distribution: mean.

studentTVariance

Student's t distribution: variance.

fPdf

F distribution: probability density at x.

fCdf

F distribution: cumulative probability P(X <= x).

fQuantile

F distribution: the value x with P(X <= x) = p (inverse CDF).

fSf

F distribution: survival probability P(X > x), the upper tail worked directly.

fMean

F distribution: mean.

fVariance

F distribution: variance.

bernoulliPmf

Bernoulli distribution: probability of exactly this outcome.

bernoulliCdf

Bernoulli distribution: cumulative probability P(X <= x).

bernoulliMean

Bernoulli distribution: mean.

bernoulliVariance

Bernoulli distribution: variance.

geometricPmf

Geometric distribution: probability of exactly this outcome.

geometricCdf

Geometric distribution: cumulative probability P(X <= x).

geometricMean

Geometric distribution: mean.

geometricVariance

Geometric distribution: variance.

negativeBinomialPmf

Negative binomial distribution: probability of exactly this outcome.

negativeBinomialCdf

Negative binomial distribution: cumulative probability P(X <= x).

negativeBinomialMean

Negative binomial distribution: mean.

negativeBinomialVariance

Negative binomial distribution: variance.

hypergeometricPmf

Hypergeometric distribution: probability of exactly this outcome.

hypergeometricCdf

Hypergeometric distribution: cumulative probability P(X <= x).

hypergeometricMean

Hypergeometric distribution: mean.

hypergeometricVariance

Hypergeometric distribution: variance.

normalSf

Normal distribution: survival probability P(X > x), accurate far into the tail.

normalLogSf

Normal distribution: ln P(X > x), the logarithm of the upper tail, finite where the probability itself is too small for a decimal: normalLogSf(40, 0, 1) is -804.608.

normalLogCdf

Normal distribution: ln P(X <= x), the logarithm of the lower tail, finite far below the mean.

gammaSf

Gamma distribution: survival probability P(X > x), accurate far into the tail.

betaSf

Beta distribution: survival probability P(X > x), accurate far into the tail.