Help summarizing certain rows and columns based on criteria provided from drop down lists

I am hoping somebody out there can help me. I have been searching the forum for several days now and I can't seem to find a good fit.

I have exported raw data to a worksheet named "xn export raw qc data". I would like to summarize certain columns of that export to a summary worksheet named "XN QC Summary". The rows and columns to summarize are determined by values selected from drop down lists that are highlighted in yellow on the 'XN QC Summary Sheet". I am trying to figure out how to calculate the average of a certain column, determined by the TEST drop down, certain rows in that TEST column determined by the LotNumber and the AnalyzerID which are also selected from the LotNumber and AnalyzerID drop downs:

For example, if I average the results for the following selections:

Lot Number: QC-31541101
Test: WBC(10^3/uL)
AnalyzerID: XN-10^11998

Average = 3.01

Now if I change the test value drop down from WBC(10^3/uL) to RBC(10^6/uL), the Average should change to 2.29

I realize this could be accomplished by filtering columns and rows within the raw data sheet. The summary page is preferred as we are a large laboratory system and numerous different locations will be 'feeding' their data into the summary. The end product would be a system wide, peer comparison of data.

Any help anyone can give is appreciated. I have attached a workbook with the worksheets mentioned above.

thanks
kim