fit_dist_gamma function

Fit Offspring Distribution to the Gamma Distribution

This function fits offspring data to a special case of the gamma distribution, in which zero values of offspring are excluded and all values are rounded to a whole number, and tests the goodness of fit using the chi-squared test.

fit_dist_gamma(dist)

Arguments

• dist: a numeric vector of data values for number of offspring per dam.

Returns

• estimate: Shape and rate parameters estimated from the supplied distribution.

• sd: Standard deviation of the shape and rate estimates.

• vcov: Variance/covariance matrix of the shape and rate estimates.

• loglik: the log-likelihood of the shape and rate estimates.

• n: The number of observations.

• statistic: The chi-squared test statistic.

• parameter: Degrees of freedom for the chi-squared test.

• p.value: P-value for the chi-squared test.

• data_gamma: Vector of values generated from a special case of the gamma distribution.

Author(s)

M. Catherine Duryea, Andrew D. Kern, Robert M. Cox, and Ryan Calsbeek

Examples

#Fit the Shape and Rate parameters to a distribution of offspring.
#Test the goodness of fit.

data(fungus)
fungus_fit<-fit_dist_gamma(fungus$Total_Offspring)
fungus_fit$fit_gamma
fungus_fit$chi_gamma
hist(fungus_fit$data_gamma)