Mean: Add all the data points together, and divide by the number of data points. The mean is the average of the data set. In this example, an estimate for the mean is approximately $3,000.
Median: The mean is the data point in the middle of the data set. In this example, an estimate for the median is approximately $3,100 per person.
Range: The difference between the largest and smallest data points. Approximately: 8,100 − 2,300 = 5,800
Interquartile Range: The range of the quartiles in the middle. Approximately 3,400 − 2,900 = 500
From both plots, the peak is located to the left of the center of the range. Therefore, it the peak is skewed left. If the peak was located to the right, it would be skewed right.
The center of the graph is toward the left. This means that most of the expenditures and the median are on the lower end of the graph, with a few outliers to the right that skew the graph positively. The range of expenditures is rather large ($5,800), which is due to the outliers. As a result, the interquartile range provides a better description of the expenditures. Those expenditures are around $3,200 per person. The only outliers on the plot are to the right, which means that a few states have higher energy expenditures; however, most of the states spend about the same amount for personal energy costs.