Excel - have range of numbers, predict average at certain points

[upplepop]

I have a large group of numbers; they are volumes at certain percentages, e.g. (54.32%, 232), (18.5%, 129), (11.98%, 89)...

What I would like to do is have Excel determine what the average volume would be for specified percentages, for example, What is the average volume at 50.00%, 60.00%, etc.

I would also like to be able to determine the standard deviations as well.

Thanks in advance for your help.

 

[MJPPaba]

Are we talking about using the correlation of coefficient, and linear regression across a population? If so there are many stadard excel function under the statistical and mathematical category which can undertake these.

Matt