Adding variability estimates to plots with geom_errrorbar()

The previous recipe can be improved. One must request a sort of a variability analysis in addition the bar chart. We came to the conclusion 9-month salary was higher for men of every rank but what if maximum women salary were much higher than men or the minimum much lower.

ggplot2 certainly has functions draw variability intervals; one of them is the geom_errorbar(). The device drawn by such function demands ymin and ymax aesthetics arguments. Variability intervals can fit information of any kind: standard deviations, minimum and maximum values. Limitations are given only by creativity.

Getting ready

To make it happen, our departure point is going to be the new_data object. Thus, we need to make sure that the car package is installed and run step 1 from Recipe Plotting a bar graphic with aggregated data using geom_col(). Next code block is doing both things:

> if( !require(car)){ install.packages('car')}
> new_data <- aggregate...