Question

IQ scores are measured with a test designed so that the mean is 120 and the standard deviation is 12. Consider the group of IQ scores that are unusual. What are the z scores that separate the unusual IQ scores from those that are​ usual? What are the IQ scores that separate the unusual IQ scores from those that are​ usual? (Consider a value to be unusual if its z score is less than minus2 or greater than​ 2.)What are the IQ scores that separate the unusual IQ scores from those that are​ usual?

Answer 1

Answer:

Step-by-step explanation:

Here a score is considered to be "unusual" if higher than 2 std. dev. from the mean OR lower than 2 std. dev. from the mean.

Thus, any score lower than (120 - 2[12]), or 96, or higher than (120 + 2[12] ), or 144, is considered to be "unusual."