Variables Affecting Driving Performance

For example, consider a hypothetical experiment concerning the driving ability of two different types of drivers - inexperienced (A1) and experienced (A2). These people will drive on one of three types of roads - first class (B1), second class (B2), or dirt (B3) - under one of two different driving conditions - day (C1) and night (C2). Thus we have a 2x3x2 factorial. The experiment will include four participants per condition (for a total of 48 participants), and the dependent variable will be the number of steering corrections in a one mile section of roadway.

Paste the results of the ANOVA below.

One point for each of the 4 things below.

a.Conduct the appropriate ANOVA (testing for homogeneity of variance) and answer the following questions.

b.What number is the average variance in each group. _______________

c.Do you have homogeneity of variance? How do you know? _____________________

d.Does the effect of driver experience depend upon road condition and whether you drive during the day or at night? How do you know? _________________________

e.Is the variability among the road conditions main effect means greater than you would expect by chance? How do you know? ______________

If you need to, follow up each significant effect using a Tukey test.

1. Was there an overall impact of driver experience on performance? If so, please put the means for that effect below describe the precise nature of that effect. Provide the specific complete statistical results to support your answer.

Main Effect of Driver Experience

InexperiencedExperienced

1. Was there an overall impact of day/night driving on performance? If so, please put the means for that effect below and describe the precise nature of that effect. Provide the specific complete statistical results to support your answer.

Main Effect of daynight

DayNight

Drivers that drive during the day made statistically fewer steering corrections than drivers that drive at night

1. Was there an overall impact of road condition on performance? If so, please put the means for that effect below and describe the precise nature of that effect.Provide the specific complete statistical results to support your answer.

Main Effect of Road Condition

First Class (b1)Second Class (b2)Dirt (b3)

11.87519.2529.187

Tukey critical difference =

Tukey conclusions

1. Does the impact of experience on driving performance depend upon whether they were driving during the day or night (collapsing over road condition)? If so please put the means for that effect below and describe the precise nature of that effect.Provide the specific complete statistical results to support your answer.

Significant Interaction of Driving Experience and Daynight

DayNightDifference

Inex

Exper

Tukey critical difference =

Tukey conclusions

1. Does the impact of experience on driving performance depend upon the road condition (collapsed over time of day). If so, please put the means for that effect below and describe the precise nature of that effect. Provide the specific complete statistical results to support your answer.

Significant Interaction of Driving Experience and Road Condition

First Class (b1)Second Class (b2)Dirt (b3)

Inexper

exper

Tukey CD=

Tukey conclusions =

1. Does the impact of Time of Day on driving performance depend upon road condition (collapsed over experience). If so, please put the means for that effect below and describe the precise nature of that effect. Provide the specific complete statistical results to support your answer.

Significant Interaction of Daynight and Road Condition

First Class (b1)Second Class (b2)Dirt (b3)

Day

Night

Tukey critical difference =

Tukey conclusions

1. Does the impact of experience on driving performance depend upon the condition of the road and whether they were driving during the day or night? If so please put the means for that effect below and describe the precise nature of that effect.Provide the specific complete statistical results to support your answer.

Aexper * Cdaynight * Btypeofroad

InexperiencedRoad Conditiond

first class (B1) second class (B2) dirt (B3) -

Day

Night

Experienced-first class (B1) second class (B2) dirt (B3) -

Day

Night

Tukey critical difference =

Tukey conclusions

inexperienced vs. experienced

Day first class

Day second class

Day third class

night first class

night second class

night third class

10. Does the impact of the condition of the road on driving performance depend upon the experience of the driver and whether they were driving during the day or night? If so, please describe the precise nature of that effect. Provide the specific complete statistical results to support your answer.

Tukey CD =

Tukey conclusions=

Inexperienced Day

Road Condition

first class (B1) second class (B2) dirt (B3) -

Tukey conclusions for Inexperienced Day=

Inexperienced Night

Road Conditiond

first class (B1) second class (B2) dirt (B3) -

Tukey conclusions for Inexperienced Night=

Experienced-Day

Road Conditiond

first class (B1) second class (B2) dirt (B3) -

Tukey conclusions for experienced Day=

ExperiencedNight

Road Conditiond

first class (B1) second class (B2) dirt (B3) -

Tukey conclusions for experienced night=

11.Suppose you wanted to conduct a simple effects analysis of a three way interaction of driver experience, road condition and day/night driving on driver performance. Below please write the F ratios (show the numerator and the denominator) that would result from a test of the Time of Day x road condition interaction separately for each level of driving experience. Also state precisely what you conclude from this.

Time of Day x road condition interaction for inexperienced drivers

F=

Time of Day x road condition interaction for experienced drivers

F=

Critical F with 2, 36 df

Conclusions: