I have another question...
According to the IQR rule, an observation is labelled as a potential outlier if it is more than
1.5xIQR above the upper quartile, or 1.5xIQR below the lower quartile, where IQR denotes the
inter-quartile range. Show that, for a sample from a normally distributed population the IQR rule
identifies any observation that is more than 2.7 standard deviations from the mean as an outlier.