If a normal distribution of scores has a mean of 55 and a standard deviation of 10, what range of values would contain 99.73% of the scores?
A) 25-85
B) 35-75
C) 30-80
D) 45-65
E) not possible to determine from the information given.

Question

Quizplus · Accepted Answer

The 99.73% range in a normal distribution is covered by ±3 standard deviations from the mean. Here, 3 standard deviations (3*10) = 30, so the range is 55-30 to 55+30, which is 25 to 85.

If a Normal Distribution of Scores Has a Mean of 55