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JMP13 fitting Defective Subpopulation Weibull; would like to constrain exponent parameter < 1




Nov 9, 2016

JMP13 fitting defective subpopulation weibull; would like to constrain exponent parameter < 1

I see that under Parametric Estimate - DS Weibull red triangle menu there is a Fix Parameter, but (a) it offers location and scale, not the Weibull exponent and (b) it seems not to allow for applying an inequality constraint to specify a maximum value for a parameter (DS exponent might ideally be sub-unity for example).




Jun 23, 2011

That is correct, JMP provides the Weibull model in both versions, the location and scale version and the shape and scale version. Fits fits the location and scale version, so that is the way that you fix one of the parameters to a given value.The transformation between versions is straight-forward, so if you have the shape or scale, you can transform it to the location or scale.

The parameter constraint is not over an interval but to a single point, like setting an intercept equal to zero.

Learn it once, use it forever!