We can assess whether there is an increasing trend above 20 mg/day by simply re-defining x 2 equal to ( x −20) + in Eq. 8 ; this approach is known as piecewise linear model.
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We can assess whether there is an increasing trend above 20 mg/day by simply re-defining x 2 equal to ( x −20) + in Eq. 8 ; this approach is known as piecewise linear model.