STDEV IF???

hi guys, sorry if this has been postd before but i have tried searching the forumns and couldnt get an answer.

what i need to do is (using Excel) obtain a STDEV from results in a column (call it column A) but ONLY when there is a particular result in another column (column B).

in case i am not explaining this i will doa demo of what i mean below:

A B
65
53 1
52 1
65
47 1

so, what i was trying to get was a STDEV for the results in column A where a 1 was present in colum B (in this case it would be a STDEV of 53,52,47).

is there anyway this can be done without extracting the results into another column?

many thanks…

adam