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A study compared three display panels used by air traffic controllers. Each disp

ID: 2929003 • 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 = 35.79, p-value = .0000; (Click to select)do not rejectreject H0

(c) Test the significance of emergency condition effects with = .05.

F = 139.36, p-value = .0000; (Click to select)do not rejectreject 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?

(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 18 26 35 13 18 24 38 13 B 17 20 30 11 11 21 31 5 C 23 32 34 8 23 30 36 15 30 25 20 15 10 Panel A Panel B Panel C

Explanation / Answer

a. The interaction plot reveals that the lines are parallel, which implies that there is no interaction between display panel and emergency conditions. Panel B takes less time. The p value (0.133) is not less than alpha=0.05, therefore, fail to rjecet null hypothesis. Cannot reject H0.

b. For display panel effect, p value is less than 0.05, therefore, reject H0.

c. For emergency condition effect, p value is less than 0.05, therefore, reject H0.

c. The pairwise comparison generated from output are as follows:

muB-muA=(-11.5483, 6.209), muC-muA=(-4.67328, 13.0840), muC-muB=(-0.8487, -14.5987)