Hi all,I have some questions about the covariants of regression.

My target: To explore the trend of CD4 level through a period of time.

Response variable: CD4 count
Explanatory variable:time

Also, the demology information is available,such as gender,occupation,income
level...

Q1,Are these variables of demology information called covariant?
Q2,How can I correct the impact of "covariant" so that I can get the
"corrected result" of CD4's change through the time period?
Q3,How to treat the covariants in regression?I've looked up to many papers
of R on regression,which treat the covariant in the same

way as the Explanatory variable,like following:
lm(CD4 ~ time + gender + income)

>From above expression of regression,it's obvious that the response variables
and covariants are treated the same way,but acturally

they are totally different.



Thanks for your help.

My best.

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