dBetaBin | R Documentation |
The function computes the probability mass function of the beta-binomial distribution.
dBetaBin(x, size, mu, theta = NULL, phi = NULL)
x |
a vector of quantiles. |
size |
the total number of trials. |
mu |
the mean parameter. It must lie in (0, 1). |
theta |
the overdispersion parameter. It must lie in (0, 1). |
phi |
the precision parameter. It is an alternative way to specify the |
The beta-binomial distribution has probability mass function
{n\choose x} \frac{Γ{(φ)}}{Γ{(μφ)}Γ{((1-μ)φ)}} \frac{Γ{(μφ+x)}Γ{((1-μ)φ + n - x)}}{Γ{(φ + n)}},
for x \in \lbrace 0, 1, …, n \rbrace, where 0<μ<1 identifies the mean and φ=(1-θ)/θ >0 is the precision parameter.
A vector with the same length as x
.
Ascari, R., Migliorati, S. (2021). A new regression model for overdispersed binomial data accounting for outliers and an excess of zeros. Statistics in Medicine, 40(17), 3895–3914. doi:10.1002/sim.9005
dBetaBin(x = 5, size = 10, mu = .3, phi = 10)
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