Herein we provide the full code to realize Figures 1 to 4 that illustrate
the article describing the `superb`

framework [@cgh21].
These figures are based on ficticious data sets that are
provided with the package superb (`dataFigure1`

to `dataFigure4`

).

Before we begin, we need to load a few packages, including `superb`

of course:

## Load relevant packages library(superb) # for superbPlot library(ggplot2) # for all the graphic directives library(gridExtra) # for grid.arrange

If they are not present on your computer, first upload them to your computer with
`install.packages("name of the package")`

.

The purpose of Figure 1 is to illustrate the difference in error bars when the
purpose of these measures of precision is to perform pair-wise comparisons. It
is based on the data from `dataFigure1`

, whose columns are

```
head(dataFigure1)
```

where `id`

is just a participant identifier, `grp`

indicate group membership (here
only group 1 and group 2), and finally, `score`

is the dependent variable.

The first panel on the left is based on stand-alone confidence intervals and is obtained with :

plt1a <- superbPlot(dataFigure1, BSFactors = "grp", variables = "score", plotStyle = "line" ) plt1a

Note that these *stand-alone* error bars could have been obtained by adding the argument
`adjustments = list(purpose = "single")`

but as it is the default value, it can be omitted.

The default `theme`

to `ggplot`

s is not very attractive. Let's decorate the plot a bit!
To that end, I collected some additional ggplot directives in a list:

ornateBS <- list( xlab("Group"), ylab("Attitude towards class activities"), scale_x_discrete(labels = c("Collaborative\ngames", "Unstructured\nactivities")), #new! coord_cartesian( ylim = c(70,130) ), geom_hline(yintercept = 100, colour = "black", size = 0.5, linetype=2), theme_light(base_size = 10) + theme( plot.subtitle = element_text(size=12)) )

so that the first plot, with these ornaments and a title, is:

plt1a <- plt1a + ornateBS + labs(subtitle="(stand-alone)\n95% CI") plt1a

The second plot is obtained in a simar fashion with just one additional argument requesting difference-adjusted confidence intervals:

plt1b <- superbPlot(dataFigure1, BSFactors = "grp", variables = "score", adjustments = list(purpose = "difference"), #new! plotStyle = "line" ) plt1b <- plt1b + ornateBS + labs(subtitle="Difference-adjusted\n95% CI") plt1b

Finally, the *raincloud* plot is obtained by changing the `plotStyle`

argument:

plt1c <- superbPlot(dataFigure1, BSFactors = "grp", variables = "score", adjustments = list(purpose = "difference"), plotStyle = "raincloud", # new layout! violinParams = list(fill = "green", alpha = 0.2) ) # changed color to the violin plt1c <- plt1c + ornateBS + labs(subtitle="Difference-adjusted\n95% CI") plt1c

All three plots are shown side-by-side with:

grid.arrange(plt1a, plt1b, plt1c, ncol=3)

and exported to a file, with, e.g.:

png(filename = "Figure1.png", width = 640, height = 320) grid.arrange(plt1a, plt1b, plt1c, ncol=3) dev.off()

You can change the smooth density estimator (the `kernel`

function) by adding to the `violinParams`

list the following attribute: `kernel = "rectangular"`

for example to have a ragged density estimator.

In the end, which error bars are correct? Remember that the *golden rule of adjusted
confidence intervals* is to look for **inclusion**: for example, is the mean of the second
group part of the possible results suggested by the first group's confidence interval? yes it
is in the central plot. The central plot therefore indicate an absence of signficant difference.
The confidence intervals being 95%, this conclusion is statistically significant at the 5% level.

Still not convinced? Let's do a *t* test (actually, a Welch test; add `var.equal = TRUE`

for the regular
*t* test; @dll17):

t.test(dataFigure1$score[dataFigure1$grp==1], dataFigure1$score[dataFigure1$grp==2], )

There are no significant difference in these data at the .05 level, so that the error bar of a 95% confidence interval should contain the other result, as is the case in the central panel.

Finally, you could try here the Tryon's adjustments (changing to `adjustments = list(purpose = "tryon")`

).
However, you will notice no difference at all. Indeed, the variances are almost identical in the two groups
(`r round(sd(dataFigure1[dataFigure1$grp ==1,]$score),2)`

vs.
`r round(sd(dataFigure1[dataFigure1$grp ==2,]$score),2)`

).

Figure 2 is made in a similar fashion, and using the same decorations `ornate`

as above with
just a different name for the variable on the horizontal axis:

ornateWS <- list( xlab("Moment"), #different! scale_x_discrete(labels=c("Pre\ntreatment", "Post\ntreatment")), ylab("Statistics understanding"), coord_cartesian( ylim = c(75,125) ), geom_hline(yintercept = 100, colour = "black", size = 0.5, linetype=2), theme_light(base_size = 10) + theme( plot.subtitle = element_text(size=12)) )

The difference in the present example is that the data are from a within-subject design with two repeated measures. The dataset must be in a wide format, e.g.,

```
head(dataFigure2)
```

This makes the left panel:

plt2a <- superbPlot(dataFigure2, WSFactors = "Moment(2)", variables = c("pre","post"), adjustments = list(purpose = "single"), plotStyle = "line" ) plt2a <- plt2a + ornateWS + labs(subtitle="Stand-alone\n95% CI") plt2a

... and this makes the central panel, specifying the `CA`

(*correlation-adjusted*)
decorelation technique:

plt2b <- superbPlot(dataFigure2, WSFactors = "Moment(2)", variables = c("pre","post"), adjustments = list(purpose = "difference", decorrelation = "CA"), #new plotStyle = "line" ) plt2b <- plt2b + ornateWS + labs(subtitle="Correlation and difference-\nadjusted 95% CI") plt2b

As seen, `superbPlot`

issues relevant information (indicated with `FYI`

messages),
here the correlation.

To get a sense of the general trends in the data, we can examine the data participants per participants, joining their results with a line. As seen below, for most participants, the trend is upward, suggesting a strongly reliable effect of the moment:

plt2c <- superbPlot(dataFigure2, WSFactors = "Moment(2)", variables = c("pre","post"), adjustments = list(purpose = "difference", decorrelation = "CA"), plotStyle = "pointindividualline" ) #new plt2c <- plt2c + ornateWS + labs(subtitle="Correlation and difference-\nadjusted 95% CI") plt2c

Just for the exercice, we also compute the plot of the difference between the scores. To that end, we need different labels on the x-axis and a different range:

ornateWS2 <- list( xlab("Difference"), scale_x_discrete(labels=c("Post minus Pre\ntreatment")), ylab("Statistics understanding"), coord_cartesian( ylim = c(-25,+25) ), geom_hline(yintercept = 0, colour = "black", size = 0.5, linetype=2), theme_light(base_size = 10) + theme( plot.subtitle = element_text(size=12)) )

We then compute the differences and make the plot:

dataFigure2$diff <- dataFigure2$post - dataFigure2$pre plt2d <- superbPlot(dataFigure2, WSFactor = "Moment(1)", variables = c("diff"), adjustments = list(purpose = "single", decorrelation = "none"), plotStyle = "raincloud", violinParams = list(fill = "green") ) #new plt2d <- plt2d + ornateWS2 + labs(subtitle="95% CI \nof the difference") plt2d

This last plot does not require decorrelation and is not adjusted for difference.
Decorrelation would not do anything as `diff`

is a single column;
difference-adjustment is inadequate here as the difference is to be
compared to a fix value (namely 0, for zero improvement)

Assembling all four panels, we get:

grid.arrange(plt2a, plt2b, plt2c, plt2d, ncol=4)

... which can be exported to a file as usual:

png(filename = "Figure2.png", width = 850, height = 320) grid.arrange(plt2a, plt2b, plt2c, plt2d, ncol=4) dev.off()

Which error bars are depicting the significance of the result most aptly? The adjusted ones seen in the central panel, as confirmed by a t-test on paired data:

t.test(dataFigure2$pre, dataFigure2$post, paired=TRUE)

The confidence interval of one moment does not *include* the result from the other moment, indicating
a significant difference between the two moments.

The novel element in Figure 3 is the fact that the participants have been recruited by clusters of participants.

We first adapt the ornaments for this example:

ornateCRS <- list( xlab("Group"), ylab("Quality of policies"), scale_x_discrete(labels=c("From various\nfields", "From the\nsame field")), #new! coord_cartesian( ylim = c(75,125) ), geom_hline(yintercept = 100, colour = "black", size = 0.5, linetype=2), theme_light(base_size = 10) + theme( plot.subtitle = element_text(size=12)) )

Then, we get an unadjusted plot as usual:

plt3a <- superbPlot(dataFigure3, BSFactors = "grp", variables = "VD", adjustments = list(purpose = "single", samplingDesign = "SRS"), plotStyle = "line" ) plt3a <- plt3a + ornateCRS + labs(subtitle="Stand-alone\n95% CI") plt3a

Here, the option `samplingDesign = "SRS"`

is the default and can be omitted.

To indicate the presence of *cluster-randomized sampling*, the `samplingDesign`

option is set to `"CRS"`

and an additional information, `clusterColumn`

is indicated to identify the column containing the cluster membership information:

plt3b <- superbPlot(dataFigure3, BSFactors = "grp", variables = "VD", adjustments = list(purpose = "difference", samplingDesign = "CRS"), #new plotStyle = "line", clusterColumn = "cluster" ) #new plt3b <- plt3b + ornateCRS + labs(subtitle="Cluster and difference-\nadjusted 95% CI") plt3b

An inspection of the distribution does not make the cluster structure evident and therefore a raincloud plot is maybe little informative in the context of cluster randomized sampling...

plt3c <- superbPlot(dataFigure3, BSFactors = "grp", variables = "VD", adjustments = list(purpose = "difference", samplingDesign = "CRS"), plotStyle = "raincloud", violinParams = list(fill = "green", alpha = 0.2), clusterColumn = "cluster" ) plt3c <- plt3c + ornateCRS + labs(subtitle="Cluster and difference-\nadjusted 95% CI")

Here is the complete Figure 3:

grid.arrange(plt3a, plt3b, plt3c, ncol=3)

This figure is saved as before with

png(filename = "Figure3.png", width = 640, height = 320) grid.arrange(plt3a, plt3b, plt3c, ncol=3) dev.off()

To make the correct *t* test in the present case, we need a correction factor called
$\lambda$. An easy way is the following [see @cl16 for more]

res <- t.test( dataFigure3$VD[dataFigure3$grp==1], dataFigure3$VD[dataFigure3$grp==2], ) # mean ICCs per group, as given by superbPlot micc <- mean(c(0.491335, 0.203857)) # lambda from five clusters of 5 participants each lambda <- CousineauLaurencelleLambda(c(micc, 5, 5, 5, 5, 5, 5)) tcorrected <- res$statistic / lambda pcorrected <- 1 - pt(tcorrected, 4) cat(paste("t-test corrected for cluster-randomized sampling: t(", 2*(dim(dataFigure3)[1]-2),") = ", round(tcorrected, 3), ", p = ", round(pcorrected, 3),"\n", sep= ""))

As seen, the proper test is returning a coherent decision with the proper error bars.

Figure 4 is an illustration of the impact of sampling among a finite population.

ornateBS <- list( xlab(""), ylab("Metabolic score"), scale_x_discrete(labels=c("Response to treatment")), #new! coord_cartesian( ylim = c(75,125) ), geom_hline(yintercept = 100, colour = "black", size = 0.5, linetype=2), theme_light(base_size = 10) + theme( plot.subtitle = element_text(size=12)) )

Lets do Figure 4 (see below for each plot in a single figure).

plt4a <- superbPlot(dataFigure4, BSFactors = "group", variables = "score", adjustments=list(purpose = "single", popSize = Inf), plotStyle="line" ) plt4a <- plt4a + ornateBS + labs(subtitle="Stand-alone\n95% CI")

The option `popSize = Inf`

is the default; it indicates that the population is presumed
of infinite size. A finite size can be given, as

plt4b <- superbPlot(dataFigure4, BSFactors = "group", variables = "score", adjustments=list(purpose = "single", popSize = 50 ), # new! plotStyle="line" ) plt4b <- plt4b + ornateBS + labs(subtitle="Population size-\nadjusted 95% CI")

We illustrate the plot along some distribution information with a violin plot:

plt4c <- superbPlot(dataFigure4, BSFactors = "group", variables = "score", adjustments=list(purpose = "single", popSize = 50 ), # new! plotStyle="pointjitterviolin", violinParams = list(fill = "green", alpha = 0.2) ) plt4c <- plt4c + ornateBS + labs(subtitle="Population size-\nadjusted 95% CI")

Which are reunited as usual:

plt4 <- grid.arrange(plt4a, plt4b, plt4c, ncol=3)

...and saved with:

png(filename = "Figure4.png", width = 640, height = 320) grid.arrange(plt4a, plt4b, plt4c, ncol=3) dev.off()

The corrected *t* test, performed by adjusting for the proportion of the population
examined [see @t12], confirms the presence of a significant difference:

res <- t.test(dataFigure4$score, mu=100) tcorrected <- res$statistic /sqrt(1-nrow(dataFigure4) / 50) pcorrected <- 1-pt(tcorrected, 24) cat(paste("t-test corrected for finite-population size: t(", nrow(dataFigure4)-1,") = ", round(tcorrected, 3), ", p = ", round(pcorrected, 3),"\n", sep= ""))

**Any scripts or data that you put into this service are public.**

Embedding an R snippet on your website

Add the following code to your website.

For more information on customizing the embed code, read Embedding Snippets.