one side test

[lulube]

proc reg data = data; 
model a = b c d; 
test b=0; 
run;

Hello, I want to do a one side test on SAS, in fact I want to test if 'b' has a positive effect on 'a' but I don't know how to do it with this code. Thanks for your help !

[PaigeMiller]

You take the p-value for the coefficient of B, and you double it.