Question 8.31

8.31 “Guitar Hero” and “Rock Band.”

Refer to the previous exercise.

  1. How would the result that you reported in part (c) of the previous exercise change if only 25% of the respondents said that they did not currently play a musical instrument?
  2. Do the same calculations for a case in which the percent is 75%.
  3. The main conclusion of the survey that appeared in many news stories was that 67% of players of “Guitar Hero” and “Rock Band” who do not currently play a musical instrument said that they are likely to begin playing a real musical instrument in the next two years. What can you conclude about the effect of the three scenarios—part (b) in the previous exercise and parts (a) and (b) in this exercise—on the margin of error for the main result?

8.31

(a) (0.641, 0.699). (b) (0.653, 0.687). (c) While it’s true that if the sample size gets smaller or bigger, the margin of error will go up or down, in all three cases, the sample is quite large and the results don’t differ that much, so the main conclusion still holds.