INTERPRETING THE MEAN AND MEDIAN
It is desired to describe the daily sales of a newspaper. A sample of sales for 70 days is obtained, and these are shown below. The sales are in 1000’s. Note: The data for this example are the same as the data used in the histogram example.
Calculate the mean and median of the daily newspaper sales. Discuss what these values indicate about the daily sales, and compare the two values.
SOLUTION
The following descriptive statistics were calculated using
StatCrunch. The mean and median are in blue.
Summary
statistics:
|
Column |
n |
Mean |
Variance |
Std. Dev. |
Std. Err. |
Median |
Range |
Min |
Max |
Q1 |
Q3 |
|
Sales |
70 |
100.057144 |
143.93872 |
11.997446 |
1.4339691 |
98.5 |
77 |
73 |
150 |
92 |
107 |
Both the mean of 100,057 and median of 98,500 indicate where the center of the data is located, and what the typical daily number of newspapers sold is. Thus, the typical number of newspapers sold daily is about 100,000. The histogram of these data is shown below. Note that 100,000 is also where the typical values are centered in the histogram.
Since the histogram is slightly skewed in a positive direction, the mean is slightly larger than the median.
A histogram of Daily Newspaper Sales
Sales are in Thousands of Papers Sold
per Day
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