#delim cr
version 6.0
/*
 Examples for the STB bulletin submission for somersd
*/

/* Open log file */
log using example1.log,replace
capture noisily{
/* Beginning of main capture block */

/* Use auto data set and define additional variables */
use auto,clear
desc
/* Create manuf variable */
gene str18 manuf=ltrim(make)
replace manuf=substr(manuf,1,index(manuf," ")-1)
replace manuf=make if(index(make," ")<=1)
tab manuf,missing
/* Create symbol variable for foreign cars */
gene str1 forsym="D"
replace forsym="F" if(foreign)

/*
 Demo of Somers' D
*/
/* Ranksum tests */
ranksum mpg,by(foreign)
ranksum weight,by(foreign)
/* Somers' D with CIs */
somersd foreign mpg weight
lincom -weight-mpg
/* Somers' D (z-transformed) with CIs */
somersd foreign mpg weight,tran(z)
lincom -weight-mpg
/* Somers' D (z-transformed and clustered) with CIs */
somersd foreign mpg weight,tran(z) cluster(manuf)
lincom -weight-mpg

/*
 Plot mpg against weight to visualize message of Somers' D
*/
grap mpg weight,s([forsym]) /*
 */ xlab(1000,2000,3000,4000,5000) ylab(0,5,10,15,20,25,30,35,40,45) /*
 */ saving(fig1.gph,replace)
/*
 Create encapsulated PostScript graphics
 (using gphpen, which I have and most Stata 6.0 users don't)
*/
gphpen fig1.gph /deps /n /ofig1.eps

/*
 Demo of Kendall's tau-a
*/
/* Significance tests */
ktau mpg mpg
ktau mpg weight
ktau mpg displ
/* Kendall's tau-a with CIs */
somersd mpg weight displ,taua
lincom weight-displ
/* Kendall's tau-a (z-transformed) with CIs */
somersd mpg weight displ,taua tr(z)
lincom weight-displ
/* Kendall's tau-a (z-transformed and clustered) with CIs */
somersd mpg weight displ,taua tr(z) cluster(manuf)
lincom weight-displ
/* Greiner's rho */
somersd mpg weight displ,taua tr(zrho)

/* End of main capture block */
}
/* Close log file and exit */
log close
exit