sense of whether inequality is increasing or decreasing. There are formal criteria, however, for this visual assessment to be precise and accurate (see below).The tabular form was chosen and adopted universally to facilitate the presentation of the distributions when total frequency is large, as well as those of each interval of the attribute in question (income, size of municipalities, peoples height, etc.). When distribution is shown for visualization only, the intervals are used; when, however, the measurement of the distributions degree of concentration is required, it is necessary to obtain the value of the average attribute of each interval.The following examples are illustrative. The first table is formed by income intervals and the second by average incomes corresponding to each interval.Example of tabular income distribution by income intervalsIncome intervalsFrequenciesa bn1b cn2c - dn3 dn4TotalNExample of tabular income distribution by average incomesIncome intervalsFrequenciesr1n1r2n2r3n3r4n4TotalNThe tabular presentation of the income distribution, therefore, indicates that, when grouped by income ranges (or intervals, or classes), precisely to be viewed, analyzed or for performing the appropriate calculations, the survey carried out in a given population matched it with each individuals respective incomes (annual, monthly, weekly averages).The end result, therefore, is the count of individuals (frequencies), with their respective average incomes grouped by ranges. In fact, the tables two columns show two series: the first of average incomes or income ranges and the second of frequencies or individuals. Each of them, in the case of income, have distinct movements, determined by the labor markets conditioning factors.The table in general is always understood as the picture resulting from counting the frequencies arranged by ranges of the attributes. It is the same for income distribution. It so happens that there is an additional possibility to view and understand such a table, as follows.As the income ranges or average incomes of each range are arranged in either increasing or decreasing order, this feature can be used to also understand the table of income distribution as ordering or a position scale, and even as a scale of prestige or social merit. The incomes of each individual grant them the places they occupy in the position, prestige or social scale. Individuals with lower incomes are at the bottom of the social position scale, while the others are above and at the top of the scale.Thus, in the income series, rn > rn-1 indicates that the group of individuals n is located in a better situation in terms of income than the group of individuals n-1. The n group therefore has a better position (whatever it is) than the n-1 group.The income distribution table therefore presents two distinct types of features. One is the counting of frequencies for each group of individuals matched to each income range. The second is the ordering or scale of the individuals, positioned according to the levels of income they earn.It is this additional feature of ordering or scale of the income distribution table that, along with the other usual feature, sustains and distinguishes the interpretation of the income inequality measurement, which will be presented below.6- Income and frequency series