Conditional median in MS Excel

Question

I\'m trying to calculate the conditional median of a chart that looks like this:

A  |  B
-------
x  |  1
x  |  1
x  |  3
x  |  
y  |  4
z  |  5

Answer 1

There is another way that does not involve the array formula that requires the CtrlShiftEnter operation. It uses the Aggregate() function offered in Excel 2010, 2011 and beyond. The method also works for min,max and various percentiles. The Aggregate() allows errors to be ignored, so the trick is to make all values that are not required cause errors. The easiest way is to do the task set above is:

=Aggregate(16,6,(B:B)/((A:A = "x")*(B:B<>"")),0.5)

The first and last parameters set the scene to do a percentile 50%, which is a median, the second says ignore all errors (including DIV#0) and the third says select the B column data, and divide it by a number which is one for all non empty values that have an x in the A column, and a zero otherwise. The zeros create a divide by zero exception and will be ignored because a/1=a and a/0=Div#0

The technique works for quartiles (with an appropriate p value), all other percentiles of course, and for max and min using the large or small function with appropriate arguments.

This is a similar construct to the Sumproduct() tricks that are so popular, but which cannot be used on any quantiles or max min values as it produces zeros which look like numbers to these functions.

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