Hi,
Could anyone please help me understand the difference between
svymean age, by(female)
and
svymean age if female=1?
If I use the second command, I sometimes will get the error message about
only one psu. I never have such a problem with the first command. How the
psus and strata are handled using the by() option? And how it is different
from using "if" command? My goal is to estimate average age by gender.
Does the first command assume eaqual size of male and female? Intuitively,
I would use the second one, or think these 2 are the same. I don't
understand why they are different.
THanks in advance for your help.
Chenghui Li
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