The distribution of hourly sales for a local family owned store is normally distributed with a mean of $225 per hour and a standard deviation of $75 per hour. Which of the following intervals contains the middle 95% of hourly sales?
A)$75 to $375
B)$150 to $300
C)$175 to $275
D)$125 to $325

Question

Quizplus · Accepted Answer

The middle 95% of a normally distributed set of data falls within two standard deviations of the mean. The mean is $225, and two standard deviations are 2 * $75 = $150. Therefore, the interval is $225 - $150 to $225 + $150, which is $75 to $375.

The Distribution of Hourly Sales for a Local Family Owned