# AMS

0th

Percentile

##### Alpha Shape Parameter Given Mean and Variance of a Standard Beta PDD.

Calculates the Alpha value required to produce a Standard (two-parameter) Beta probability density distribution with defined mean and variance or standard deviation.

##### Usage
AMS(mean, var, sd = NULL)
##### Arguments
mean

The mean of the target Standard Beta probability density distribution.

var

The variance of the target Standard Beta probability density distribution.

sd

The standard deviation of the target Standard Beta probability density distribution.

##### Value

A numeric value representing the required value for the Alpha shape-parameter in order to produce a Standard Beta probability density distribution with the target mean and variance.

• AMS
##### Examples
# NOT RUN {
# Generate some fictional data. Say, 100 individuals take a test with a
# maximum score of 100 and a minimum score of 0, rescaled to proportion
# of maximum.
set.seed(1234)
testdata <- rbinom(100, 100, rBeta.4P(100, .25, .75, 5, 3)) / 100
hist(testdata, xlim = c(0, 100))

# To find the alpha shape-parameter of a Standard (two-parameter) Beta
# distribution with the same mean and variance as the observed-score
# distribution using AMS():
AMS(mean(testdata), var(testdata))
# }

Documentation reproduced from package betafunctions, version 1.2.2, License: CC0

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