I need a bit of help. Ive got a excel sheet, with lots of data for
200 patients (1 Patient per row). One test that was performed on
these patients had the possibility of one of 20 results. However,
for one of these results (Number 20) the patient could present with
one or more of the 20 diseases. How to i write a formula to
automatically adjust the figures as what i need is to determine the
true prevalence of every disease in this sample.

For example:

1. Blue
2. red
3. pink
4. green
5. yellow
6. orange
......
.....
20. Blue/red&pink (SO I NEED EXCEL TO ADD ONE AT EACH OF THESE)

PLEASE HELP.