options nocenter ls=79 ps=50;

data biotron;
   infile 'biotron.dat' firstobs=2;
   input block A B C D;

data b; set biotron;
   yield = A; variety = 'A'; output;
   yield = B; variety = 'B'; output;
   yield = C; variety = 'C'; output;
   yield = D; variety = 'D'; output;
   drop A B C D;

proc anova;
   class block variety;
   model yield = block variety;
   means variety / lsd;

proc glm;
   class block variety;
   model yield = block variety;
   random block;
   lsmeans variety / stderr pdiff;

proc mixed;
   class block variety;
   model yield = variety;
   random block;
   lsmeans variety;