Let the ordered sample observations be denoted by

( being the smallest and the largest). Our suggested check for normality is to plot the pairs. Suppose we believe that the observations come from a distribution with mean 0, and let be the ordered absolute values of the .
A half-normal plot is a probability plot of the .
More specifically, since , a half-normal plot is a plot of the pairs. The virtue of this plot is that small or large outliers in the original sample will now appear only at the upper end of the plot rather than at both ends. Construct a half-normal plot for the following sample of measurement errors, and comment:
.