Presentation on theme: "Cheat or Honest? An Experiment Department of Statistics Rachel Fewster."— Presentation transcript:
Cheat or Honest? An Experiment Department of Statistics Rachel Fewster
Catch the Cheats! I am a fraud investigator, you are the suspects! Each group picks a status: Honest or Cheat You can change the status that you pick if you like, but WRITE DOWN your new status on your slip (no erasing the evidence!!)
HONEST GROUPS: 1.Pick a column on the atlas sheets: Population, Area sq km, or Area sq miles 2. Pick a start-point wherever you like 3. Copy down 100 entries from your column: just the first two digits is enough. E.g. for 2 691 write 2600 (dont round it) For 782 write 780.
CHEATING GROUPS: 1.Make up the numbers out of your head! 2.Again just use two digits, e.g. 530, 72000, 8800000, … 3.You can use the atlas sheets as a guide to range of numbers, but you must MAKE YOUR NUMBERS UP.
Now for the investigation! 1.UNDERNEATH your numbers … Make out a TALLY LIST for FIRST DIGITS in your output:
123456789123456789 I I III I IIII I II III 1.Make out a TALLY LIST for FIRST DIGITS in your output:
123456789123456789 I III I IIII I II III 2. Rewrite the tally as numbers 3. Title First Digit 113014123113014123 First Digit
123456789123456789 I III I IIII I II III 113014123113014123 First Digit 7. Fold your paper, tear off the tallies from the rest. 8. Write your name on the tallies section and hand in!
Can we catch the cheats ??? See the R demonstration at: http://www.stat.auckland.ac.nz/~fewster/benford/