PROC TTEST: WHERE statement

[nicktr18]

Hi, all. I am trying to run a two-sample ttest on a variable with a class that contains three levels. I understand that, by using a WHERE expression, I can omit the extra level. However, my code is failing me.  

proc ttest data=totalmvp;
     var pt0;
     class unit;

     where unit= ;
run;

I do not know what to place after the "unit=" in the expression. I am trying to keep levels called "offense" and "defense" while omitting a level called "special teams." 

[PGStats · Accepted solution]

where unit in ("offense" "defense");

[GFW]

or if you have no missing value of unit, the following is either an option

where unit ^in ("special teams");