Add only the cells after a particular number in the previous cell in the same column

[DrSues02]

Also, using the formula that you stated above for the Y's and N's.

I am using =SUMPRODUCT((Purdue!D21000="Y")*(Purdue!D31001="N")) t
figure out the number of times a Y immediately follows a N.

However, once again, I am trying to find a percentage. I need to fin
the number of times a Y immediately follows a N (which is the formul
above) divided by the total number of times a N occurs with either a
or N afterwards.

Here is the basic formula:

# of times a N is followed by a Y/(# of times an N is followed by a
or N)

Any ideas

 

[LanceB]

=SUMPRODUCT((purdue!D21000="Y")*(purdue!D31001="N"))/COUNTIF(D21000,"N")