http://www.aaa3.net/iq-test-score-scale/
How I can find the standard deviation?
How do I answer this question, scores of adults on the Wechsler Adult Intelligence Scale (common "IQ" test) follow a normal distribution. The mean 95% of the scores on this test range from 70 to 130. What is the standard deviation of test results? I know it's 7.5, but how do you find?
I thought that + / – 2 sigma covers 95 percent which is 70 to 130 -2 to + 2 sigma sigma. This would mean that sigma is given by: 2 Sigma – (-2 sigma) = 130-70 = 60 4 sigma sigma = 15
SMART IQ / INTELLIGENCE QUOTIENT TEST
