Evidence Gathering Notes
The simplest way to gather evidence without causing a major disruption is to do the following:
- Determine the number of fax machines on campus: You can do that by getting an electronic copy of the phone directory, extracting the "fax" column, and doing a unique sort on that column. This can be done with a one line command in unix. The result is the number of fax machines you have on campus.
- Select the participants: Randomly select 50 fax numbers from the phone book. Fax them the notice and instructions to save all their unsolicited faxes for 3 weeks and send them in via interdepartmental mail.
- Collect the results: At the end of the 3 week period, you should have 50 "packets". If you have less than this, it's fine...it will just be a smaller statistical sample which we then just extrapolate to the full number of fax machines. So if we only get 40 packets back and there are 800 fax machines, we'd multiple the number in hand by 20 to estimate the total number of unwanted faxes during the period.
We can then use statistics to accurately extrapolate the total junk fax volume. We can also perform statistical analysis on the samples to determine confidence levels in the extrapolation.