Table 1: Confidence interval of regression line by driving condition.

Condition Sample size se Lower (α = 0.001) Upper (α = 0.001)
Acc. ≥ 0 1800 0.84x + 0.01 1.55 0.84x + 0.01 - (1.55 * 3) 0.84x + 0.01 + (1.55 * 3)
Acc. < 0 900 0.87x - 0.24 1.96 0.87x - 0.24 - (1.96 * 3) 0.87x - 0.24 + (1.96 * 3)

Note: Acc. = acceleration; = slip; se = standard error of slip; and x = acceleration.