MMPI-2: Confidence intervals for random responding to the F, F Back, and VRIN scales

Several studies have investigated random responding to the F, F Back, and VRIN scales. Only one study attempted to provide practical cutoff scores for these scales, but was unable to reach definitive cutoffs. This study uses the normal approximation to the binomial distribution and provides confidence interval bounds for random responding at the 95, 90, and 85% levels for the F, F Back, and VRIN scales. The possibility that humans asked to respond randomly produce F, F Back, and VRIN scores different from computer-generated random scores was investigated. The results show nonsignificant differences between human and computer responses for the F and F Back scales and mixed results for the VRIN scale.