Comparison of Markov models. For each amino acid (x-axis), the bars present the ratios of observed vs predicted counts of repeats with length five. Model standard deviations are indicated by whiskers. Predictions for the standard sequence model of positional independence (a Markov model of order zero) are compared to predictions from higher order models (bar shading), including the highest order model possible for this repeat length. Higher order models yield ratios closer to one, which represents the perfect agreement of observation and prediction.