Rec letter over academic ability needed?

[SomeNerd]

Hi all,

I am applying for stats phd programs with my bachlors degree in math. I do not have math subject GRE score but my general GRE Q is 168. And I have all A's in my upper level math classes. I am planning to have all 3 of rec letters from the professors I have only done research with. I have not taken classes with any of my rec letter writers. Is that okay not to have a letter commenting on my academic ability? 

Thanks in advance for your help!

[bayessays]

That's fine, the most important thing is to get letters from people with quantitative PhDs who know you well.  Usually someone you did research with is more able to give valuable feedback.  Your grades can speak for themselves.