In multiple linear regression, the revised fitting model, add the nonlinear term, run time error,
Ins_model2 & lt; - lm (earlier ~ age + age2 + children + + sex, bmi bmi30 * smoker + region, data=https://bbs.csdn.net/topics/insurance)
# add age2, then an error
The Error in the eval (predvars, data, env) : object 'age2' not found
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