M7MBA wrote:The mean score in a certain test is 80. If the test scores have a normal distribution and the standard distribution is 7, what percent of examinees score between 66 and 94?
A) 50%
B) 68%
C) 82%
D) 96%
E) 98%
[spoiler]OA=D[/spoiler]
Source: Princeton Review
Since (66 - 80)/7 = -2 and (94 - 80)/7 = 2, we see that the scores from 66 to 94, inclusive, are within 2 standard deviations of the mean. Therefore, by the 68-95-99.7 rule, approximately 95% of the examinees' scores are between 66 and 94, inclusive.
Answer: D
