probability question

[psusnoop]

I have a data set of numbers that we run here in the lab and I have been working on figuring out the probability that these numbers repeat. I have run into a roadblock though.
I'm having problems figuring out what formula to use to calculate the probability. For instance on worksheet 3 I have the data set with the date ran. I would like to calculate how many times these numbers come up.

I have included the workbook for help.

Thanks in advance.

[shg]

You need to provide more information as to how the numbers are selected and explain your question more clearly.