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Hi, Is this method broken in R? I am using it to find roots of the following function: f(x) = 2.5*exp(-0.5*(2*0.045 - x)) + 2.5*exp(-0.045) + 2.5*exp(-1.5*x) - 100 It is giving an answer of -38.4762403 which is not even close (f(x) = 2.903809e+25 for x=-38.4762403). The answer should be around 0.01-0.1. This function should converge.. Even for a simple function like f(x) = exp(-x) * x, it gives

...othesis. It may well not be an important hypothesis, or a particularly interesting hypothesis, or a hypothesis that the experimenter actually cares about. It is substantially different from the hypothesis which is tested by SSA when there is no interaction. (Different, but related.) Bill Venables fulminates that consideration of such a hypothesis is contrary to the fundamental philosophy of statistcial modelling, and thereby an abomination in the sight of God, and probably Politically Incorrect to boot. This may well be so. Nonetheless it ***is*** a well-defined and meaningful hypothesis. Rathe...

Dear R members, I have been trying to find out whether one can use multivariate regression trees (for example mvpart) to analyze repeated measures data. As a non-parametric technique, CART is insensitive to most of the assumptions of parametric regression, but repeated measures data raises the issue of the independence of several data points measured on the same subject, or from the same plot