To compare three brands of computer keyboards, four data entry specialists were randomly selected. Each specialist used all three keyboards to enter the same kind of text material for 10 minutes, and the number of words entered per minute was recorded. The data obtained are given in the table below.  Using these data, SST = 392.6667, SSB = 143.54833, and SSE = 2.6667.

                                                      Keyboard Brand

       Data Entry Specialist               A       B       C

                   1                                     77     67     63

                   2                                    71     62     59

                   3                                    74     63     59

                   4                                     67     57     54    

Use Tukey simultaneous 95 per cent confidence intervals to make pairwise comparisons of the keyboard brand effects on the mean number of words entered per minute.  Which keyboard brand maximizes the mean number of words entered per minute?