Using the data from Exercises 4 and 5, compare the 20% trimmed means of the experimental group to the control, taking into account grade. Also test for no interactions using lincon and linconb. Is...

Using the data from Exercises 4 and 5, compare the 20% trimmed means of the experimental group to the control, taking into account grade. Also test for no interactions using lincon and linconb. Is there reason to suspect that the confidence interval returned by linconb will be longer than the confidence interval returned by lincon?