Question 637898: On a police sergeant’s examination, the historical mean score was 80 with a standard deviation of 20. Four officers who were alleged to be cronies of the police chief scored 195, 171, 191, and 189, respectively, on the test. This led to allegations of irregularity in the exam.
(a) Convert these four officers’ scores to standardized z-values.
(b) Do you think there was sufficient reason to question these four exam scores? What assumptions are you making?
(Data are from Detroit Free Press, March 19, 1999, p. 10A)
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! On a police sergeant’s examination, the historical mean score was 80 with a standard deviation of 20. Four officers who were alleged to be cronies of the police chief scored 195, 171, 191, and 189, respectively, on the test. This led to allegations of irregularity in the exam.
(a) Convert these four officers’ scores to standardized z-values
z(195) = (185-80)/20 = 105/20 = 5.25
Do that for each of the scores
----------------------------------
(b) Do you think there was sufficient reason to question these four exam scores? What assumptions are you making?
Absolutely. Assuming a normal distribution of test taker scores.
these four scores are at the upper extreme of scoring.
=============
Cheers,
Stan H.
=================
|
|
|
