- (E) Scores on the WISC are normally distributed. The WISC has a mean of 100 and a standard
deviation of 15. Banu, therefore, scored two standard deviations above the mean: (130 – 100)/15
= 2. Z scores are a measure of the distance from the mean in units of standard deviation, so Banu
has a z score of +2, making possible answers D and E. Percentile is a measure of the percent of
test takers who scored at or below a particular score. We know that 50 percent of the test takers
scored at or below the mean. We know that an additional 34 percent of scores fall between the
mean and one standard deviation above the mean, and we know that another 13.5 percent of scores
fall between one and two standard deviations above the mean. Adding these numbers together tells
us that Banu scored at the 97.5th percentile, making the answer E.
marvins-underground-k-12
(Marvins-Underground-K-12)
#1