Stat 1040
Chapter 29 Solutions

  1. We would expect 5% of them to be found guilty - this is data snooping.

  2. The question makes no sense - there is no box model - there are no samples, nor any randomization.

  3. The difference is practically significant, but statistical significance makes no sense because the data are for the whole population.

    1. The question makes sense and the difference in attitudes is important.
    2. The question makes sense because they took probability samples. However, we cannot answer it because they are cluster samples.
    3. The two percentages are 48% and 25%. The two standard errors are 1.6% and 1.4%. The SE for the difference is 2.1% so z=(48-25)/2.2 = 10 and the P-value is tiny. We reject the null and conclude that attitudes changed.