Russel-Research-Method-in-Anthropology

Sampling 167
25
Number of Households
20
15
10
5
0
0 5 10 15
Children per Household
Figure 6.2b. Distribution of the number of children in Ticuna households.
SOURCE: Adapted from data in A. Oyuela-Caycedo and J. J. Vieco Albarracín, ‘‘Aproximación cuantitativa a
la organización social de los ticuna del trapecio amazónico colombiano,’’ Revista Colombiana de Antropología,
Vol. 35, pp. 146–79, table 6, p. 159, 1999.
many population subgroups (that is, independent variables) you want to deal
with simultaneously in your analysis; (3) the size of the subgroup that you’re
trying to detect; and (4) how precise you want your sample statistics (or
parameter estimators) to be.
1. Heterogeneity of the population. When all elements of a population have the
same score on some measure, a sample of 1 will do. Ask a lot of people to tell
you how many days there are in a week and you’ll soon understand that a big
sample isn’t going to uncover a lot of heterogeneity. But if you want to know
what the average ideal family size is, you may need to cover a lot of social
ground. People of different ethnicities, religions, incomes, genders, and ages may
have very different ideas about this. (In fact, these independent variables may
interact in complex ways. Multivariate analysis tells you about this interaction.
We’ll get to this in chapter 21.)
2. The number of subgroups in the analysis. Remember the factorial design
problem in chapter 5 on experiments? We had three independent variables, each
with two attributes, so we needed eight groups (2 3 8). It wouldn’t do you much
good to have, say, one experimental subject in each of those eight groups. If
you’re going to analyze all eight of the conditions in the experiment, you’ve got
to fill each of the conditions with some reasonable number of subjects. If you