Jul 25, 2013, 8:34:24 PM7/25/13
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I'm an Eureqa Newbie (just downloaded the software) with probably a really stupid question, but I am hoping someone can help me.
First off sorry about the political topic here, but I am trying to
figure out the effects of gun laws on violent crime rates.
# of violent crime per capita is my independent variable
The dependent variables that I have are:
a = population density
b = average home price
c = average education level
d = distance from police stations
e = if concealed handguns are outlawed
My last variable, e, is a dummy variable. I set it to 0 in areas that don't allow concealed handguns and set it to 1 in areas that do.
When I use Eureqa to try and fit an equation to all these data, it comes up with an equation using a, b, c, & d. However, if doesn't use e at all in the equation. So at first I was thinking, "ok so this shows that gun laws have no effect on crime rates."
then I took the residuals (observed data - Eureqa equation), and i just
plotted these in excel. Through a little bit of manual work, I found that I
could improve the objective function (mean squared error) by 2% by just
adding in a linear term with e to my equation.
all this my question is does Eureqa just not work at fitting dummy
variables? Or what techniques do i need to use to get it to incorporate
a dummy variable into my equation?
Thanks in advance for the help.