Subject: How does air temperature affect the frequency of sound waves?

I am doing a science project on the effect of air temperature on 
pitch/sound wave frequency, and i would like some background information 
on how the molecules in the air can affect frequency so that i can make a 
proper hypothesis. The textbook i've looked at mention a definite change 
in the speed of sound waves with increased temperature and increased 
collision of molecules, but is the 
frequency in any way dependent on this collision, and if yes, why?

Re: How does air temperature affect the frequency of sound waves?