= 
0 
) 
PART IL.—THE THEORY OF ATTRIBUTES. 
CHAPTER L 
NOTATION AND TERMINOLOGY. 
1-2. Statistics of attributes and statistics of variables : fundamental character 
of the former—3-5. Classification by dichotomy—6-7. Notation for 
single attributes and for combinations—8. The class-frequency—9. 
Positive and negative attributes, contraries—10. The order of a class— 
11. The aggregate—12. The arrangement of classes by order and 
aggregate—13-14. Sufficiency of the tabulation of the ultimate class- 
frequencies—15-17. Or, better, of the positive class-frequencies—18. 
The class-frequencies chosen in the census for tabulation of statistics 
of infirmities—19. Inclusive and exclusive notationsand terminologies. 
1. THE methods of statistics, as defined in the Introduction, 
deal with quantitative data alone. The quantitative character 
may, however, arise in two different ways. 
In the first place, the observer may note only the presence or 
absence of some attribute in a series of objects or individuals, and 
count how many do or do not possess it. Thus, in a given 
population, we may count the number of the blind and seeing, 
the dumb and speaking, or theinsane and sane. The quantitative 
character, in such cases, arises solely in the counting. 
In the second place, the observer may note or measure the 
actual magnitude of some variable character for each of the 
objects or individuals observed. He may record, for instance, the 
ages of persons at death, the prices of different samples of a 
commodity, the statures of men, the numbers of petals in flowers. 
The observations in these cases are quantitative ab initio. 
2. The methods applicable to the former kind of observations, 
which may be termed statistics of attributes, are also applicable 
to the latter, or statistics of variables. A record of statures of 
men, for example, may be treated by simply counting all measure- 
ments as fall that exceed a certain limit, neglecting the magnitude 
of excess or defect, and stating the numbers of tall and skort (or