help for ^qbeta4^

Quantile-quantile plot for data vs fitted beta distribution ------------------------------------------------------------

^qbeta4^ varname [^if^ exp] [^in^ range] [ ^,^ ^a^lpha^(^#^)^ ^b^eta^(^#^)^ ^gr^id graph_options ]

Description -----------

^qbeta4^ plots the quantiles of varname against the quantiles of a two-parameter beta distribution with shape parameters alpha and beta. By default, alpha and beta are taken from S_2 and S_3, which is where ^beta4^ puts maximum likelihood estimates of them.

Note: this is the original version of ^qbeta^, written for Stata 4. Users of Stata 8 up should switch to ^qbeta^.

Options -------

^alpha(^#^)^ sets alpha to #.

^beta(^#^)^ sets beta to #.

^grid^ adds grid lines at the .05, .10, .25, .50, .75, .90, and .95 quantiles.

graph_options are any of the options allowed with ^graph, twoway^; see help for ^graph^.

Examples --------

. ^beta4 hail^ . ^qbeta4 hail^

Author ------ Nicholas J. Cox, University of Durham, U.K. n.j.cox@@durham.ac.uk

Acknowledgement ---------------

Alan Feiveson pointed out that ^invfprob()^ could be used to obtain the inverse of the beta distribution function.

Also see --------

On-line: help for @graph@, @beta4@ (if installed), @pbeta4@ (if installed)