The proportional odds model is a popular regression model for ordinal categorical responses, which has a rather strong underlying assumption, the proportional odds assumption. The rejection of the null assumption, however, is not very informative since a statistical significance does not...

One hundred years ago Karl Pearson derived an approximate formula for the correlation between ratios with a common divisor and cautioned to be wary of correlating ratios. The exact formula for the correlation between ratios is derived. It can provide a better reference point of no connection...

We consider the accuracy estimation of a classifier constructed on a given training sample. The naive resubstitution estimate is known to have a downward bias problem. The traditional approach to tackling this bias problem is cross-validation. The bootstrap is another way to bring down the high...