Norms for a new test of mental ability were obtained from a large sample of the general population.The mean of the test was set to 100 and the standard deviation was 15.Approximately what percentage of the population would fall within the range bounded by scores of 85 and 115?
A) 20 percent
B) 68 percent
C) 2 percent
D) 98 percent

Question

Quizplus · Accepted Answer

This question is based on the empirical rule, also known as the 68-95-99.7 rule. According to this rule, approximately 68% of the population falls within one standard deviation (in either direction) of the mean. In this case, one standard deviation is 15 points, so scores between 85 and 115 are within one standard deviation of the mean. Therefore, approximately 68% of the population would fall within this range.

Norms for a New Test of Mental Ability Were Obtained