P__disp: A function to calculate Pearson Chi2 and its dispersion...

In msme: Functions and Datasets for "Methods of Statistical Model Estimation"

Description

This function calculates Pearson Chi2 statistic and the Pearson-based dipersion statistic. Values of the dispersion greater than 1 indicate model overdispersion. Values under 1 indicate under-dispersion.

Usage

P__disp(x)

Arguments

x	the fitted model.

Details

To be used following glm and glm.nb functions.

Value

pearson.chi2	Pearson Chi2 value.
dispersion	Pearson-basde dispersion.

Author(s)

Joseph Hilbe and Andrew Robinson

References

Hilbe, J.M., and Robinson, A.P. 2013. Methods of Statistical Model Estimation. Chapman & Hall / CRC.

See Also

glm, glm.nb

Examples

data(medpar)
mymod <- glm(los ~ hmo + white + factor(type), 
             family = poisson, 
             data = medpar)
P__disp(mymod)

Example output

Loading required package: MASS
Loading required package: lattice
pearson.chi2   dispersion 
 9327.983216     6.260391 

msme documentation built on May 2, 2019, 5:07 a.m.