A study compared three display panels used by air traffic controllers. Each disp
ID: 2930877 • Letter: A
Question
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 table gives the resulting data and the MINITAB output of a two-way ANOVA of the data.
Figure 12.12
(a) Interpret the interaction plot in the above table. Then test for interaction with = .05.
(b) Test the significance of display panel effects with = .05.
F = 29.73, p-value = .0000;
H0
(c) Test the significance of emergency condition effects with = .05.
F = 75.70, p-value = .0000;
H0
(d) Make pairwise comparisons of display panels A, B , and C by using Tukey simultaneous 95 percent confidence intervals. (Round your answers to 2 decimal places. Negative amounts should be indicated by a minus sign.)
(e) Make pairwise comparisons of emergency conditions 1, 2, 3, and 4 by using Tukey simultaneous 95 percent confidence intervals. (Round your answers to 2 decimal places. Negative amounts should be indicated by a minus sign.)
(f) Which display panel minimizes the time required to stabilize an emergency condition? Does your answer depend on the emergency condition? Why?
minimizes the time required to stabilize an emergency condition.
, there is
(g) Calculate a 95 percent (individual) confidence interval for the mean time required to stabilize emergency condition 4 using display panel B. (Round your answers to 2 decimal places.)
Confidence interval [ , ]
Emergency Condition Display Panel 1 2 3 4 A 19 25 34 12 19 26 37 12 B 16 20 28 14 11 19 28 7 C 22 30 33 10 25 30 39 16 35 30 25 20 15 10 Panel A Panel B Panel CExplanation / Answer
First of all, there are some discrepancies between the actual data and the summarized results. First three questions are explained based on given result whether the remaining are given depending on the data provided.
a)The interaction lines are almost parallel to each other. This means that the patterns of impact of different panels are same for different emergency conditions. Therefore there are no interaction effect between panels and emergency conditions. From the analysis of variance table, we have found that the p-value for testing the interaction effect is 0.605. Hence, there is no significant interaction effect.
b)To test the display panel effect, it is found that the p-value is 0.0000 which means that there are significant differences among different display panels.
c)To test the emergency condition effects, the p-value for testing that problem is 0.0000. This means average time to stabilize the emergency condition is significantly different for different emergency conditions.
d)$panel
diff lwr upr p adj
A-B 5.125 1.62 8.63 0.0055567
A-C -2.625 -6.13 0.88 0.1555126
B-C -7.750 -11.26 -4.24 0.0002001
e)$cond
diff lwr upr p adj
1-2 -6.33 -10.84 -1.83 0.0061446
1-3 -14.50 -19.01 -9.99 0.0000031
1-4 6.83 2.33 11.34 0.0034983
2-3 -8.17 -12.67 -3.66 0.0008240
2-4 13.17 8.66 17.67 0.0000085
f)Panel B minimizes the time required to stabilize an emergency condition. This does not depend on emergency condition since the interaction effect is not significant.
g)The required confidence interval is given by [9.38, 18.62].
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