Fig. 5.

Standard error bars do not show variability and do a poor job of showing precision. The figure plots one data set six ways. The leftmost lane shows a scatter plot of every value, so is the most informative. The next lane shows a box-and-whisker plots showing the range of the data, the quartiles, and the median (whiskers can be plotted in various ways, and do not always show the range). The third lane plots the median and quartiles. This shows less detail, but still demonstrates that the distribution is a bit asymmetrical. The fourth lane plots mean with error bars showing plus or minus one standard deviation. Note that these error bars are, by definition, symmetrical so give you no hint about the asymmetry of the data. The next two lanes are different than the others as they do not show scatter. Instead, they show how precisely we know the population mean, accounting for scatter and sample size. The fifth lane shows the mean with error bars showing the 95 % confidence interval of the mean. The sixth (rightmost) lane plots the mean plus or minus one standard error of the mean, which does not show variation and does a poor job of showing precision