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mlr (version 2.9)

generateCritDifferencesData: Generate data for critical-differences plot.

Description

Generates data that can be used to plot a critical differences plot. Computes the critical differences according to either the "Bonferroni-Dunn" test or the "Nemenyi" test. "Bonferroni-Dunn" usually yields higher power as it does not compare all algorithms to each other, but all algorithms to a baseline instead. Learners are drawn on the y-axis according to their average rank. For test = "nemenyi" a bar is drawn, connecting all groups of not significantly different learners. For test = "bd" an interval is drawn arround the algorithm selected as baseline. All learners within this interval are not signifcantly different from the baseline. Calculation: $$ CD = q_{\alpha} \sqrt{(\frac{k(k+1)}{6N})}$$ Where $q_\alpha$ is based on the studentized range statistic. See references for details.

Usage

generateCritDifferencesData(bmr, measure = NULL, p.value = 0.05, baseline = NULL, test = "bd")

Arguments

bmr
[BenchmarkResult] Benchmark result.
measure
[Measure] Performance measure. Default is the first measure used in the benchmark experiment.
p.value
[numeric(1)] P-value for the critical difference. Default: 0.05
baseline
[character(1)]: [learner.id] Select a learner.id as baseline for the test = "bd" ("Bonferroni-Dunn") critical differences diagram.The critical difference Interval will then be positioned arround this learner. Defaults to best performing algorithm. For test = "nemenyi", no baseline is needed as it performs all pairwise comparisons.
test
[character(1)] Test for which the critical differences are computed. “bd” for the Bonferroni-Dunn Test, which is comparing all classifiers to a baseline, thus performing a comparison of one classifier to all others. Algorithms not connected by a single line are statistically different. then the baseline. “nemenyi” for the posthoc.friedman.nemenyi.test which is comparing all classifiers to each other. The null hypothesis that there is a difference between the classifiers can not be rejected for all classifiers that have a single grey bar connecting them.

Value

[critDifferencesData]. List containing: ]. List containing:

See Also

Other benchmark: BenchmarkResult, benchmark, convertBMRToRankMatrix, friedmanPostHocTestBMR, friedmanTestBMR, getBMRAggrPerformances, getBMRFeatSelResults, getBMRFilteredFeatures, getBMRLearnerIds, getBMRLearnerShortNames, getBMRLearners, getBMRMeasureIds, getBMRMeasures, getBMRModels, getBMRPerformances, getBMRPredictions, getBMRTaskIds, getBMRTuneResults, plotBMRBoxplots, plotBMRRanksAsBarChart, plotBMRSummary, plotCritDifferences

Other generate_plot_data: generateCalibrationData, generateFilterValuesData, generateFunctionalANOVAData, generateLearningCurveData, generatePartialDependenceData, generateThreshVsPerfData, getFilterValues