Russel-Research-Method-in-Anthropology

668 Chapter 21
English, prior urban experience, internal vs. external control (feeling that you
do or don’t control what happens to you), and so on. Using stepwise multiple
regression, Graves and Lave eliminated variables (like English proficiency,
which vanished when they controlled for education) and settled on the following
equation:
STARTING WAGE .87 10 EDUC .08 VT
.13 PW .17 MARSTAT .11 FO
where EDUC is the number of years of education beyond 10 (education only
made a difference in starting wage after the 10th year), VT is the level of
vocational training (skilled, like carpentry, vs. semiskilled, like house painting),
PW is the highest premigration wage a man earned on the reservation,
MARSTAT is marital status (married or unmarried), and FO is father’s occupation
(whether the migrant’s father was a wage laborer or not—many Navajos
in those days were sheep herders).
The equation says: Start with 87 cents an hour (remember, this was the mid-
1960s); add 10 cents an hour for every year of education beyond 10; add 8
cents if the man had strong vocational skills; add 13 cents for each dollar the
man had earned in his best job before migrating (in those days, the median
premigration wage was $1.50 an hour), add 17 cents if the man is married, and
add 11 cents if his father had worked for wages.
R 2 for this equation is .54, which means that the equation accounts for 54%
of the variance in starting wage.
Now that you know how it works, here are two more examples of multiple
regression. John Poggie (1979) was interested in whether the beliefs of Puerto
Rican fishermen about the causes of success in fishing were related to their
actual success in fishing. He measured success by asking six key informants
to rank 50 fishermen on this variable. Since his research was exploratory, he
had a wide range of independent variables, three of which he guessed were
related to fishing success: the fishermen’s expressed orientation toward delaying
gratification (measured with a standard scale), their boat size, and their
years of experience at the trade.
The deferred gratification measure accounted for 15% of the variance in the
dependent variable; years of experience accounted for another 10%; and boat
size accounted for 8%. Together, these variables accounted for 33% of the
variance in the success variable.
Emmanuel Mwango (1986) studied the decision by farmers in Malawi to
devote part of their land to growing new cash crops (tobacco and hybrid
maize) rather than planting only the traditional crop, called ‘‘maize of the
ancestors.’’ His units of analysis were individual farms; his dependent variable
was the ratio of land planted in tobacco and hybrid maize to the total land