On police sergeant's examination, historical mean score was 80 with standard deviation of 20. Four officers who were alleged to be cronies of police chief scored 195, 171, 191, and 189, respectively, on test. This led to allegations of irregularity in exam.
Convert these four officers' scores to standardized z-values.
Do you believe there was adequate reason to question these four exam scores? What suppositions are you making?
Z values are 5.75, 4.55, 5.55, 5.45.