Using Standard Deviation
The mean can be used to describe the typical or common value in a data set.
The standard deviation describes a data set by giving the average of the distances from the mean. The greater the range of the data, the greater the standard deviation.
The average (arithmetic mean) supermarket checkout wait time is 4 minutes with a standard deviation of 1 minute 37 seconds (1.6 minutes).
(a) The average wait time in Atlanta, Georgia is 1 standard deviation below the mean. What is the average wait time in Atlanta?
(b) The average wait time in Washington, D.C. is 8 minutes 23 seconds (8.38 minutes). How many standard deviations is Washington’s wait time from the mean?