Question

given the mean of a data set is 20.6 and the standard deviation is 2.2, where will about 68% of the data lie? 18.4 to 22.8 20 to 21 18.4 to 20.6

Explanation:

Step1: Recall the empirical rule

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

Step2: Calculate the lower bound

Lower bound = Mean - Standard deviation. Given Mean = 20.6 and Standard deviation = 2.2, so Lower bound = 20.6−2.2 = 18.4.

Step3: Calculate the upper bound

Upper bound = Mean+ Standard deviation. So Upper bound = 20.6 + 2.2=22.8.

Answer:

A. 18.4 to 22.8