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Questions related from Jochen Wilhelm
Given there is some k-step (k=3 or 5 or 7 etc) Likert data with "absolutely no" on one side, "absolutely yes" on the other side, and "neutral" in the middle. A correct way to analyze such...
08 August 2020 1,222 5 View
Using RStudio and rMarkdown, I have an ioslides presentation (an html file). On one of the slides I want to have a link (cross-ref) to another slide in the same html. I did not find any useful...
29 May 2020 2,906 0 View
It's a weighted least-squares polynomial regression, so it's based on assuming normal errors, and the normal probability model is parametric. However, in some statistics book and online statistics...
29 October 2018 3,100 6 View
I have two models to predict "Survival" (S in (0;1)) from a "Dose" (D, D≥0): a 2-parameter Weibull model:S(D) = exp( -exp(a*logD-b) ) and a so-called "multi-target model":S(D) = 1 - ( 1-exp(-D/t)...
28 January 2016 536 7 View
Consider following case: There are k different groups, but only the mean difference between 2 of these groups should be tested (t-test, consider the assumptions are met and alpha and beta are...
15 October 2015 8,044 11 View
Short history: As I understood can the normalized (profile) likelihood be used to get the CI of an estimate. "Normalized" means that the function will have a unit integral. This works beautifully...
06 December 2014 8,888 5 View
A parameter of a statistical model should be estimated from iid data. For simplicity, let's consider a single-parameter model. The likelihood principle sais that the best estimate for the...
19 March 2014 4,823 56 View
I want to plot data for a two-factorial experiment in a simple boxplot. The attached diagram shows an example. The grouping structure of the second factor should be indicated by horizontal lines...
13 February 2014 1,002 8 View
I tried to find out why the deviance in GLMs is defined as -2*log(LR) (with LR being the likelihood ratio). Why the factor -2? Often, authors state that this way the deviance for a normal model...
29 April 2013 1,920 3 View
Background: From a binomial experiment (k successes in n trials), the proportion of successes in the "population" is estimated by p = k/n. This estimate has a standard error of SE =...
15 February 2013 3,849 9 View
I am not familiar with the grid package. I usually use "plot" (graphics) to show data and set the arguments xlim and ylim to define the visible parts of the x- and y-axes. I would like to this for...
30 November 2012 9,563 7 View
In many texts I find the statement that the likelihood is a normal-Gamma, e.g. here: http://www.cs.ubc.ca/~murphyk/Papers/bayesGauss.pdf (3.1, 3.2). I never found anything explaining HOW this is...
24 October 2012 1,545 43 View
There is a couple of error models (probability distributions) where I do understand the derivation in terms of going from simple processes where you have limited knowledge (uncertainty) to the...
19 September 2012 9,783 10 View
I know that Euler solved this somehow for a=1 and came to the value of e. I also found a series expansion that Euler developed. However, is there someone who could explain the derivation ending up...
14 September 2012 2,027 3 View
Does anyone know sources/references with derivations of the normal distribution, at best ones with explanations that can be understood by people without mathematical background? I am aware of the...
13 September 2012 3,698 3 View
I am looking for an example to determine the coefficients of a GLM by maximizing the (log)likelihood, preferrably using R. The optimization (search algorithm) is not the problem; this can be done...
10 September 2012 3,357 6 View
It's well known that proportions (real valued data in [0,1]) can be modelled using beta regression models. If the values are in other intervals with known limits, one can always scale the data...
01 January 1970 6,680 18 View
