2
votes
1answer
74 views

Confusion with Chi-Square test

I have an extremely simple question regarding chi-square test. So far I have found two different formulas for it: $$ \chi^2=\sum\frac{(x_o-x_e)^2}{x_e} $$ and $$ ...
1
vote
1answer
157 views

Efficient fitting of noncentral chi-squared distribution to data?

I am looking for the most efficient way to fit a noncentral chi-squared distribution with fixed d.o.f. to a given data set. So the inputs are d.o.f. and the data and the output should be the ...
2
votes
1answer
600 views

$\chi^2$ fitting with correlated errors

I have been doing some fitting using the fairly standard expression, $$\chi^2 = \sum_i \frac{(y_{i} - F(x_{i}, \theta))^2}{\sigma_{i}^{2}}$$ where y is my measured data, $\sigma$ is the experimental ...
1
vote
0answers
173 views

What are alternatives to uniform distribution when trying to fit observed data distribution?

I have a dataset of 500 observations and I have to find the best fitting distribution. If I look at the histogram of the data and the QQ plot my data seems to follow an uniform distribution. But a ...
1
vote
1answer
213 views

What is the distribution of a chi-square minimizing function?

Suppose I have a set of $N$ experimental points of the form \begin{equation} \{x_i, y_i, d_i\}, \end{equation} where $i=1,...,N,$ and $d_i$ are errorbars for $y_i$. To fit the data, I minimize the ...