Vlookup and mean formulas

Are you looking for the AVERAGEIFS() function? =AVERAGEIFS($I$7:$I$23,$C$7:$C$23,"Field Blank")

Hi

Thank you for your reply! I might be looking for the AverageIFS function, I will have to see what it does. I don't always know what cells the field blanks will be in. They will change with every job I do. This is a sheet we would use mulitple times a day for different projects.

I need to calculate the mean of the field blanks (this increases as the job goes on; the requirement is 2 blanks or 10% of the total number of samples whichever is greater)

Does that make sense?

The averageifs function is close, but I probably didn't explain it correctly. I need to calculate the mean of the blanks.

So the long goal of what I need is as follows:
Calculate and report fiber density on the filter, (fibers/mm²), by dividing the average fiber count
per graticule field, minus the mean field blank count per graticule field, by the graticule
field area, (approx. 0.00785 mm²)

Density = ((I7/K7)-(mean of field blanks; Column L/total of Column K (only when used)) / 0.00785

So I am trying to get a column that recognizes and populates the MEAN (NOT AVG) when I input field blanks.

For the spread sheet attached here the mean for field blanks is (5+3)/200 = 0.04

Does that make sense?

It looks like a weighted average then? More of a SUMIFS() function then? =SUMIFS($I$7:$I$23,$C$7:$C$23,"Field Blank")/SUMIFS($K$7:$K$23,$C$7:$C$23,"Field Blank")

SUMIFS() help file: https://support.microsoft.com/en-us/...6-611cebce642b