Figure 11.2 illustrated the concept of accuracy and precision with the use of a hypothetical game of darts. We will continue with this hypothetical game whose rules differ from the standard competition game.

In this game we throw N darts and the goal is to get as many of them as possible close to the center of the dart board. The measure of “closeness” that we will use is the rms (root-mean-square) distance of the N darts to the center of the dart board, the bullseye. There are six players involved in this dart competition. Each player has her or his own way of throwing darts.

Choose the number of darts that are being thrown and the player.

1. If each player throws only one dart, which player would you back in a competition? (By “back”, we mean bet money on that player winning.)


2. Of the two players Jack and Tobin, which player is more accurate when 15 darts are thrown?


3. Of the two players Jack and Tobin which player is more precise when 15 darts are thrown?


4. Do either of the answers to the above two questions change when 101 darts are thrown?


5. Repeat your experiments with 15 darts but now for players Casey and Yael.


6. Repeat your experiments with 47 darts but now for players Jamie and Johanna.


7. Which of the six players do you think is the best according to the criterion of “closeness”?


8. The definition of precision as developed in this chapter can lead to interesting situations. Which player, Casey or Yael, is more precise according to the definition?


9. Does that definition match your intuitive feeling about their capacity for being precise?