Reconciling 2 or more data sets when data volume is varying and wide?

I am a real estate researcher by trade. I am doing a report on median and mean home prices

in my town over a comparable time period. i.e.- quarter to quarter and year over year.



My problem is this:



for example, in the 4th Qtr of 2009, there was 35 sales with a median price of $335,500

and a mean price of $343,960.



In Q1 of 2010 there were only 11 sales with a median of $349,900 and a mean of $368,245



My problem is comparing two or more data sets, that have a large delta in the number of sales.

In this instance, 35 versus 11. With a such a low volume of sales in Q1 I would think that the data is more volatile, yes?



Is there a formula or solution to