*NKNW765.sas, homogeneity tests using data in Table 18.2;
options nocenter;

data a1; infile 'c:\Ageorge\Purdue\Stat512\Textdata\CH18TA02.DAT';
   input  strength type;
proc print data=a1; run;

proc glm data=a1; 
   class type; 
   model strength=type;
   means type/hovtest=levene(type=abs); 
run;

*variations: use hovtest=levene(type=square) hovtest=bartlett;