IQ scores on the WAIS test approximate a normal curve with a mean of 100 and a standard deviation of 15. What IQ score is identified with A. the upper 2 percent, that is, 2 percent to the right (and 98 percent to the left)?
B. the lower 10 percent?
C. the upper 60 percent?
D. the middle 95 percent? [Remember, the middle 95 percent straddles the line perpendicular to the mean (or the 50th percentile), with half of 95 percent, or 47.5 percent, above this line and the remaining 47.5 percent below this line.]
E. the middle 99 percent?