# Tagged Questions

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173 views

### Compare fits of model to transformed and untransformed response

I want to compare data that proportions among three different groups e.g.: ...
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### 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 ...
63 views

### Estimating a linear function mapping from n-dim to 1-dim [closed]

I'm coming from a computer science domain with an estimation problem that I'm trying to address. My background isn't statistics, so I apologize if the terminology is bad. I've been reading various ...
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### Questions about Nolan's stable.exe program

I'm using J. Nolan's free stable.exe program to fit the pareto-levy stable model to some income data. This is option 3 "fit a bivariate sample" in the program. In the instruction text file it is ...
307 views

### Online fitting for normal distributions

I was wondering if there exist efficient online or dynamic algorithm for fitting a normal distribution to data as it comes in. I am interested in two variants: The algorithm is fed data points one ...
208 views

### Finding a trend in variance

I have written a little function that samples from a normal distribution with linearly changing variance ...
2k views

### How to get parameters from a quadratic fit in Stata?

Using the Stata graph twoway command, I have created a scatterplot with a quadratic best fit line, using the qfit command. How ...
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### fitting with a large number of variables

I have been performing a relatively routine fit on data for some time. I fit the data to a fairly simple semi-empirical function. For each data point I perform repeated experiments to build a ...
1k views

### How to get a confidence interval on parameters that were fitted using multiple functions and datasets at once?

I use matlab a lot to fit functions to datasets. I then need to determine some kind of error estimate on the fitted parameters. Say I have a dataset of $N$ points which is given by the points ...
619 views

### Computing the mode of data sampled from a continuous distribution

What are the best methods for fitting the 'mode' of data sampled from a continuous distribution? Since the mode is technically undefined (right?) for a continuous distribution, I'm really asking 'how ...
141 views

### Is it possible to fit a data curve to another data curve?

Is it possible to fit a data curve to another data curve? Please see this plot I do not have the model for the black data curve or I don't want to model it. But I want to see how the red data ...
375 views

### Can anyone explain quantile maximum probability estimation (QMPE)?

Heathcote, Brown & Mewhort (2002, PDF) present Quantile Maximum Probability Estimation (originally termed Quantile Maximum Likelihood Estimation but later corrected) as a method of fitting ...
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### Is this a reasonable approach to fitting distributions?

Take the task of fitting an a priori distribution like the ex-Gaussian to a collection of observed human response times (RT). One method is to compute the sum log likelihood of each observed RT given ...
838 views

### Soft and Hard EM (Expectation Maximization)

What is the difference between soft and hard expectation maximization? EDIT: ok, i've found out this paper: http://ttic.uchicago.edu/~dmcallester/ttic101-07/lectures/em/em.pdf that explain quite well ...
672 views

### Fitting GAMM model in R

when fitting GAMM with R, I would like to know why when the smooth function is linear, the confidence interval is zero around the middle (the dotted lines are crossing each other at the middle)
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### What is the distribution of a chi-square minimizing function?

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

### Undefined link function in gamma distribution

The nonlinear model I am fitting gamma distribution with inverse or log is not converging. There is one observation having zero value in the response variable. Does this zero affects to model the ...
267 views

### Plugging in mean values/proportions to a logistic regression with continuous-discrete interaction

I have a logistic regression (in SAS, for reference) with continuous and categorical predictors (with reference coding), and an interaction term between one of each type (assume for now that the ...