1. Suppose that you are surrounded by the proverbial 100 elephants. Your machine gun has 200 bullets, and you nearly instantaneously fire them all randomly at the elephants. You can expect to be trampled by how many elephants? (choose best answer: 5, 13, or 54) What is the likelihood that elephant #33 is among those that trample you? (choose: 5.8%, 13.5%, 54.1%)

2. How many elephants got hit by 2 or more bullets? (choose: 12, 60, 73)

3. How many bullets would you have needed to fire randomly such that you'd expect to have to run away from only one elephant? (choose: 460, 534, 769)

4. What's the probability that elephant #33 would have been hit by the first bullet out of the gun? What'd be the probability of both #33 and #54 being hit by the first and second bullets, respectively, out of the gun?

5. Suppose you have a liter of susceptible bacterial culture at 1 x 10⁸ cfu/ml and a phage suspension of 2 x 10¹¹ pfu/ml. How much phage suspension must you add to the bacterial culture to infect 90% of the bacteria? (choose: 0.9 ml, 1.15 ml, 12.6 ml)

6. What did Tarzan say when he saw elephants coming down the trail? (see end)

7. Draw the Venn diagram illustrating the portion of E. coli that were simultaneously infected by both T2 and T4 in a culture where the numbers of T4 = E. coli, and T2 was twice that of T4.

8. Using the illustration in Problem 7, what portion of the cells escaped the first round of infection? (choose: 2%, 5%, 22%) What portion gave rise to phenotypically mixed phages? (choose: 21.3%, 54.6%, 78.2%)

9. There are many homeless people on the streets of Washington DC. You and your nine friends want to count them. You each take a rubber theater stamp, go your separate random ways, and begin randomly walking through neighborhoods. You each stamp exactly 20 previously unstamped homeless people with blue ink on the backs of their hands. Two days later, the ten of you do the same, but with red ink. This time you notice that 30 people now have both red and blue stamps on their hands. How many homeless people are in the area? (It is this method that is used to count the number of sparrows in a forest, or the fish in a pond, or...)

10. You suspect that the roulette table might be rigged, and you begin keeping tabs on where the ball falls. There are 38 places in the numbered wheel for the ball to fall. After 190 spins, five numbers remain unhit, and 11 have been hit 4 times. Is this likely an honest wheel? (Profs Poisson and Descartes actually invented roulette as a machine for testing this mathematics!)

11. One hundred students (evenly divided by sex) are blindfolded, put on a bus, and driven on a heavily overcast day for several hours to a place where none of them has been before. One by one, the students are taken off the bus, unblindfolded, and asked to point to the direction where they 'feel' the university is located. The quadrants least "hit" were noted according to gender. What is the random probability that only one of the males would point to one particular quadrant of the compass? What is the random probability that 10 of the women would all point to the same quadrant? (The outcome of an anthropological study in England some years ago was that the women distributed their pointings randomly over all four quadrants, and the males never pointed at one of the quadrants (and it was in the opposite direction from where their university was actually situated)! What would Profs. Poisson and Descartes say to that!)

12. Your teacher has a playing card in hand. What is the probability that it shows the card that you had thought of? (ans.: No, not 1/52! It's 100%!)

Look in a mirror and hold the paper just a certain way to see the answer to question six:

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