Suppose we want to study the errors found in the performance of a simple task.
We ask a large number of judges to report the number of people seen entering a major department store in one morning. Some judges will miss some people,
and some will count others twice,
so we don’t expect everyone to agree.
Suppose we find that the mean number of shoppers reported is 975 with a standard deviation of 15.
Assume the distribution of counts is normal.