The scores of students on a standardized test are normally distributed with a mean of 300 and a standard deviation of 40. Between what two values do 99.7% of the test scores lie?
A) 260 to 340
B) 220 to 380
C) 297 to 303
D) 180 to 420

Question

Quizplus · Accepted Answer

According to the empirical rule (68-95-99.7 rule) for a normal distribution, 99.7% of data falls within three standard deviations of the mean. Therefore, the range is mean ± 3*standard deviation = 300 ± 3*40 = 300 ± 120 = 180 to 420.

The Scores of Students on a Standardized Test Are Normally