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Figure 2.6 Family Income Distribution
The distribution of family incomes is likely to be nonsymmetrical because some incomes can be
very large in comparison to most incomes. In this case the median or the mode is a better
indicator of central tendency than is the mean.
A final measure of central tendency, known as the mode, represents the value that occurs most
frequently in the distribution. You can see from Figure 2.6 "Family Income Distribution" that the
mode for the family income variable is $93,000 (it occurs four times).
In addition to summarizing the central tendency of a distribution, descriptive statistics convey
information about how the scores of the variable are spread around the central
tendency. Dispersion refers to the extent to which the scores are all tightly clustered around the
central tendency, like this: