12.49 Time levels of scale, continued. Refer to the previous exercise.

  1. (a) Run the ANOVA and report the results.

  2. (b) Use a multiple-comparisons method to compare the three groups. State your conclusions.

  3. (c) The researchers hypothesized that the more fine-grained the time unit presented to a participant, the smaller the reported interval would be. To test this, they performed a simple linear regression using the group labels 1, 2, and 3 as the predictor variable. They found the slope (b = 27.8) significantly different from 0 (P < 0.005) and thus concluded the data supported their hypothesis. Do you think this is an appropriate way to test their hypothesis? Explain your answer.