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| From | Stefan Nijssen <stefannijssen@gmail.com> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | st: Interpreting Non-Linear Least Squares |
| Date | Sat, 23 Apr 2011 16:58:24 +0200 |
Dear Statalist users,
In interpreting my variables, I have come upon the point to let Stata's non-linear least squares function calculate the exponent best fitting my data. However, interpreting the results I am struggling a bit. To me, the function I am looking for will be one like:
Y = b0 + b1*(Var)^b2
Y being the dependent, Var the independent. Now it might very well be the case that the answer is right in front of me, however somehow to me it seems different.
The NL least squares provides the following output, stating the estimated function has the form:
Y = b0 + b1*b2^ebitda
Source | SS df MS
-------------+------------------------------ Number of obs = 141
Model | 409394.932 2 204697.466 R-squared = 0.1496
Residual | 2327596.39 138 16866.6405 Adj R-squared = 0.1373
-------------+------------------------------ Root MSE = 129.8716
Total | 2736991.32 140 19549.938 Res. dev. = 1769.474
3-parameter asymptotic regression, oas = b0 + b1*b2^ebitda
------------------------------------------------------------------------------
oas | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
/b0 | -336.6996 165.5611 -2.03 0.044 -664.0642 -9.335052
/b1 | 688.8096 178.0674 3.87 0.000 336.7163 1040.903
/b2 | .9999999 3.13e-09 3.2e+08 0.000 .9999999 .9999999
------------------------------------------------------------------------------
Parameter b0 taken as constant term in model & ANOVA table
I feel a little stupid asking this, but can anyone give me some clues on how to read this?
Thanks a lot,
Stefan Nijssen
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