statistics question-

Question

in the U.S, the average IQ is 100 with a standard deviation of 13. What percentage of the population score above an 80?

How do I solve this? and how does it differ from measuring a lower iq opposed to an "above" IQ.

Answer 1

calculate z = (80-100)/13 = -20/13= about -1.5385

use z tables to find area under the normal curve or use a statistics calculator

Pr(greater than 80) = about 93.804%

Pr(less than 80) = 1- Pr(greater than 80) = about 1-93.804 = .06.196%