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 that the distribution of
counts is normal.
75% of the counts would be less than – 3 pts.
95% of the counts would be between and – 3 pts.