Frequency Circular Reference - Again!!

[Guest]

I posted a message a few hours ago regarding my problem with a frequency
formula I was trying to use with students' grades on a spread sheet. Biff
answered and solved my problem. I did what he suggested and it worked!! (A
copy of my problem and Biff's response is below this paragraph.) Then I hit
a key by mistake and the whole thing got screwed up. So, armed with Biff's
solution, I entered the same information Biff suggested, in the exact cell
cells and rows, but now it does not work! I am totally flumoxed since it
worked 5 minutes ago. Anyway, if Biff is out there, or anyone else with a
solution, I'd sure appreciate the help. Here's the messaging:

 

[Max]

Just a guess ..

if you used

=FREQUENCY(B50:B60,C50:C57)

did you enter it with

key combo of CTRL,SHIFT,ENTER

(instead of just pressing ENTER)