# Tagged Questions

Questions on (linear or nonlinear) regression, the fitting of functions that best approximate empirical data.

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### GLM for Poisson Regression for Soccer Ratings Not Converging

I have been trying to formulate a model of soccer matches to help me predict the outcomes. The model I'm trying to formulate involves using Poisson regression to assign attack and defence ratings to ...
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### Can I adjust linear growth of a a subpopulation to a linear decay of the general population?

I need to estimate the amount of CF patients in Poland in the next four years. I have: estimations of the Polish population for the future years a CF patients' register for the last couple of years ...
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### Show $\hat{\beta}$ and $s^2$ are independent?

I have the model: $y=X{\beta}+{\epsilon}$ I know $\hat{\beta}=(X'X)^{-1}X'y$ and that it is an unbiased estimator of ${\beta}$ and that $s^2=\hat{\epsilon}'\hat{\epsilon}/(n-k)$ and is an unbiased ...
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### Is there a site that will allow me to calculate a best fit for a set of data?

I have a bunch of x's and their corresponding y values, but do not have a Wolfram Pro account. Is there another site where I can input my dataset and have it spit out a best-fit regression (be it ...
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### Showing Hat matrix equal specific values

Consider a one way layout model $y_{ij}$ = $\mu_i + e_{ij}$ (1 $\leq$ i $\leq$ a, 1 $\leq$ j $\leq$ $n_i$) where a = 3 and $n_1$ = 2, $n_2$ = 3, $n_3$ = 4. Show that the hat matrix for this design ...
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### Orthonormal Matrix weighted regression

$Q$ is a rectangular matrix with orthonormal columns. A linear system composed of $$Qx= b$$ is really easy to solve as: $$Q'Q=I$$ hence: $$x=Q'b$$ Given that $Q$ is orthonormal can this be used to ...
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### Logistic regression algorithm in Casio and Texas Instruments calculators

When using logistic regression on a Casio or Texas Instruments calculator, the output is of the form $$f(x) = \frac{c}{1+ae^{-bx}}$$ The problem I have (when teaching in a class where both types of ...
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