find average among positive or negative values in excel

In a spreadsheet I have positive and negative values in a column. I need to find the average of both of them. How can I do this in excel / open o开发者_StackOverflow社区ffice spreadsheet?

Thank you.

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Use SumIf() and divide by CountIf(), using ">0" or "<=0" as criteria. See help for both functions syntax, which is simple.