Question

given that a set of scores have a normal distribution, a mean of 54, and a standard deviation of 3: what is the range of the middle 68% of the distribution? 52 - 55 51 - 57 48 - 60 45 - 63

Explanation:

Step1: Recall empirical rule

In a normal - distribution, about 68% of data lies within 1 standard deviation of the mean.

Step2: Calculate lower bound

Lower bound = mean−standard deviation = 54 - 3=51.

Step3: Calculate upper bound

Upper bound = mean + standard deviation = 54+3 = 57.

Answer:

B. 51-57