dataFigure1 | R Documentation |
The data, taken from \insertCitec17superb, is an example where the "stand-alone" 95\% confidence interval of the means returns a result in contradiction with the result of a statistical test. The paradoxical result is resolved by using adjusted confidence intervals, here the different-adjusted confidence interval.
data(dataFigure1)
An object of class data.frame.
doi: 10.5709/acp-0214-z
library(ggplot2) library(gridExtra) data(dataFigure1) options(superb.feedback = 'none') # shut down 'warnings' and 'design' interpretation messages ## realize the plot with unadjusted (left) and ajusted (right) 95% confidence intervals plt1a <- superbPlot(dataFigure1, BSFactors = "grp", adjustments=list(purpose = "single"), variables = c("score"), plotStyle="bar" ) + xlab("Group") + ylab("Score") + labs(title="95% CI\n") + coord_cartesian( ylim = c(85,115) ) + geom_hline(yintercept = 100, colour = "black", linewidth = 0.5, linetype=2) plt1b <- superbPlot(dataFigure1, BSFactors = "grp", adjustments=list(purpose = "difference"), variables = c("score"), plotStyle="bar" ) + xlab("Group") + ylab("Score") + labs(title="Difference-adjusted 95% CI\n") + coord_cartesian( ylim = c(85,115) ) + geom_hline(yintercept = 100, colour = "black", linewidth = 0.5, linetype=2) plt1 <- grid.arrange(plt1a,plt1b,ncol=2) ## realise the correct t-test to see the discrepancy t.test(dataFigure1$score[dataFigure1$grp==1], dataFigure1$score[dataFigure1$grp==2], var.equal=TRUE)
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