HOME-STUDY DRIVER EDUCATION
A supplementary analysis was also conducted comparing correctly assigned non-driver training students in PEN to comparable students in the other courses who were assigned only after PEN was added to the study. The results, not shown, were consistent with the other analyses, suggesting that there was no bias in the other PEN comparisons resulting from comparing them to students in the other instruction methods who had been assigned prior to the time PEN was introduced into the study.
The results, not shown, of the supplementary analysis used to determine if the relative effectiveness of the instruction methods varied across the providers did not indicate a statistically significant Instruction Method x Provider School interaction on exit exam knowledge scores (p > .05). Hence, the results discussed above were the same regardless of the provider school attended.
CPI Attitude Comparisons
A higher exit exam CPI attitude score indicates more of an internal locus of control, and that having a higher internal locus of control is associated with lower accident risk. Hence, a higher attitude score indicates a safer attitude for students to have after completing a driver education course. Table 6 presents the mean exit exam attitude scores, standard deviations, and sample sizes for each instructional method and statistical comparison. The attitude means are also shown in Figure 2. Table 7 presents the results of the ANOVAs and the mean difference between each home-study mean attitude score and the classroom instruction mean attitude score. Negative mean differences would indicate that classroom students had safer attitudes than did home- study students, whereas positive mean differences would indicate that the home-study students had better attitudes. The mean attitude differences that were significantly different from classroom are asterisked in Table 7.
Mean CPI Attitude Score (M), Standard Deviation (SD), and Sample Size (n) for Each Driver Education Instruction Method by Statistical Comparison
No driver training
Note. Higher mean attitude scores indicate safer attitudes.
Driver education instruction method
n 484 413 117 288 151 137