Dear all,
  I have two variables, y and x. It seems that the relationship between them
is Piecewise Linear Functions. The cutpoint is 20. That is, when x<20, there
is a linear relationship between y and x; while x>=20, there is another
different linear relationship between them.
How can i specify their relationships in R correctly?
# glm(y~I(x<20)+I(x>=20),family = binomial, data = point)  something like
this?
 Thanks a lot.

-- 
With Kind Regards,

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Zhi Jie,Zhang ,PHD
Tel:+86-21-54237149
Dept. of Epidemiology,School of Public Health,Fudan University
Address:No. 138 Yi Xue Yuan Road,Shanghai,China
Postcode:200032
Email:epistat@gmail.com
Website: www.statABC.com
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