Comparison Distribution Descriptives
calculate a comparison distribution and associated descriptive statisics.
compdist(a, b, model, output, lambda1, lambda2, trim, strat1, strat2)
a |
a vector containing the sum of square errors or -2 * log likelihood estimates derived using modelling strategy 1. |
b |
a vector containing the sum of square errors or -2 * log likelihood estimates derived using modelling strategy 2. |
model |
type of regression model. Either "linear" or "logistic". |
output |
logical. If output is TRUE the function will return two graphical representations of the comparison distribution. |
lambda1 |
a vector or matrix containing the estimated shrinkage factors derived using strategy 1 |
lambda2 |
a vector or matrix containing the estimated shrinkage factors derived using strategy 2 |
trim |
logical. If trim is TRUE a "trimmed" comparison distribution will be returned, along with a victory rate and median precision ratio derived using the trimmed distribution. The trimmed distribution only contains precision ratios within a range of plus or minus two times the interquartile range around the median precision ratio. |
strat1 |
a list containing the strategy name and strategy-specific parameter values. |
strat2 |
a list containing the strategy name and strategy-specific parameter values. |
This function works within compare to calculate the comparison
distribution of strategy 2 against strategy 1. If trim == TRUE, a
truncated distribution consisting of +/- 2 * interquartile range around the
median precision ratio.
The victory rate for linear regression is the left tail probability with a cut-off of 1. The victory rate for logistic regression instead taken at a cut-off of 0. For more details, refer to the accompanying PDF document.
If output == TRUE the function will plot a histogram of the distribution
and a scatterplot of the precision (SSE or -2 log likelihood) of strategy 2 against
strategy 1. Points that lie below the red or blue line represent trials in which
strategy 2 outperformed strategy 1 (the victory rate).
For details of returned values and examples see compare.
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