A study compared three display panels used by air traffic controllers. Each display panel was tested for four different simulated emergency conditions. Twenty-four highly trained air traffic controllers were used in the study. Two controllers were randomly assigned to each display panel?emergency condition combination. The time (in seconds) required to stabilize the emergency condition was recorded. The following tablegives the resulting data and the JMP output of a two-way ANOVA of the data.

Emergency Condition Display Panel 1 2 3 4 A 17 25 31 14 14 24 34 13 B 15 22 28 9 12 19 31 10 21 29 32 15 24 28 37 19 Least Squares Means Estimates Panel Estimate Condition Estimate A 21 . 500000 17 . 166667 to 18 . 250000 24 . 500000 WN C 25 . 625000 32 . 166667 4 13.333333 Analysis of Variance Sum of Mean Source DF Squares Square F Ratio Model 11 1482 . 4583 134. 769 32 . 6713 Error 12 49 . 5000 4. 125 Prob > F C. Total 23 1531. 9583 <. effect tests sum of source nparm df squares f ratio prob> F Panel 2 218.5833 26.4949 <. condition . .8047 panel tukey hsd all pairwise comparisons quantile="2.66776," adjusted df="12.0," adjustment="Tukey" difference std error t ratio prob> | t Lower 95% Upper 95% A B 3. 25000 1. 015505 3.20 0 . 0194* 0 . 5409 5. 95912 A -4 . 12500 1 . 0155 -4. 06 0 . 0042* -6. 8341 -1. 41588 to : -7. 37500 1 . 015505 -7.26 | t Lower 95% Upper 95% -7.3333 1. 172604 -6.25 0 . 0002* -10 . 8146 -3. 8521 -15 . 0000 1. 172604 -12.79