An automotive parts manufacturer is testing three potential halogen headlight designs, one of which ultimately will be promoted as providing best-in-class nighttime vision. The distance at which a traffic sign can be read in otherwise total darkness is the variable of interest. Since older drivers often have lower visual acuity, driver age must be controlled in this experiment. The following results (in feet) were obtained from sampling 12 drivers (four age groups for each headlight design).

a. Use Excel to generate the appropriate ANOVA table at the 5% significance level.
b. At the 5% significance level, can you conclude that the mean nighttime viewing distance is different among the headlight designs? Practically speaking, what does your conclusion imply?
c. At the 5% significance level, was including the blocking variable Driver Age beneficial to this experiment?

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Driver Age Factor B) Below 30 30-45 46-59 60-up Headlight Design (Factor A) Design 1 Design 2 Design 3 268 243 249 214 293 254 224 238 .80 254 231 205