On the measurement of concentration and variability of characters

摘要

1. The concept of concentration of a character and various indices proposed for its measurement. Purposes of the present note. 2. On a measure of the concentration that does not depend on the distribution of the character. The concentration ratio. 3. Various arithmetic procedures for the determination of the concentration ratio according to the available statistical information. 4. Concentration for some human physiological characters and for some economic characters. 5. Concentration ratio for general cases and for positive cases. Transition formula. 6. Relationship between the concentration ratio and some graphical representation of the distribution of wealth. 7. Graphical procedures for determining the concentration ratio. 8. Further considerations on the graphical representation of the concentration ratio. 9. Relationship between the concentration ratio and the mean difference. 10-11. Related considerations. 12. Concentration ratio for truncated seriations and concentration ratio for the whole seriation. Their relationships. 13. Conclusions.