12.39 Contrasts for multitasking. Refer to the previous exercise. Let μ1, μ2, . . . , μ7 represent the mean scores for the seven conditions. The first four conditions refer to off-task behaviors, while the last three conditions represent different sorts of controls.

  1. (a) The researchers hypothesized that the average score for the off-task behaviors would be lower than that for the paper-and-pencil control condition. Write a contrast that expresses this comparison.

  2. (b) For this contrast, give H0 and an appropriate Ha.

  3. (c) Calculate the test statistic and approximate P-value for the significance test. What do you conclude?