3
votes
1answer
54 views
+50

Estimating a function $f$ of a random vector $\mathbf{x}$ by a subset of the coordinates of $\mathbf{x}$ after a rotation of the input space

Suppose I have $$h=f(\mathbf{x})$$ with $f$ a deterministic function and $\mathbf{x}=(x_1,\ldots,x_n)$ a random vector of known distribution. I'm not using the capital letter notation for random ...
4
votes
2answers
82 views
+50

Alternatives to multilevel model with log transformed outcome

I'm working with linear mixed-effects model in Stata. Dataset has three levels of 100k observations, nested in 500 regions, nested in 70 regions. Currently my modelling strategy is to use ...
3
votes
0answers
104 views
+50

Comparing unbalanced groups with ANOVA/Kruskal-Wallis when one group has only 1 observation

I would like to compare a continuous variable across 5 health status groups, but one of the groups has only 1 observation. Would an ANOVA/Kruskal-Wallis be valid? What can I do about the group with ...
0
votes
0answers
26 views
+50

How to properly show the efficiency of a process?

I'm no statistician but my background is in computer science. At work, we are trying to improve the efficiency of a system where 5 people (A-E) each produce one part of a report and send it to 2 key ...
2
votes
0answers
38 views
+100

Problems with representing and analysing non-network data as a network?

Suppose I have a dataset with 200 observations of 30 categorical variables. The dataset describes websites and different kinds of design features they deploy (or do not deploy). If I were to convert ...
16
votes
2answers
312 views
+150

Are all models useless? Is any exact model possible — or useful?

This question has been festering in my mind for over a month. The February 2015 issue of Amstat News contains an article by Berkeley Professor Mark van der Laan that scolds people for using inexact ...
0
votes
3answers
85 views
+50

Card deck shuffling, what is the probability that four lowest card of a suit are distributed to all four players?

In 4-player trick-taking game where taking a trick constitute a penalty (e.g. Hearts), I've often seen the card 5 (the fourth-lowest rank in a suit, when 2 is the lowest and Ace is the highest) takes ...
1
vote
0answers
28 views
+100

Align noisy point clouds

I have a point cloud $X$ that, I suspect, is a translate of a Gaussian-corrupted version of a subset of a larger cloud $Y$, both high-dimensional ($d$ is at least 100 and ideally 10,000). What is the ...
4
votes
2answers
109 views
+200

Regression: why test normality of overall residuals, instead of residuals conditional on $\hat{y}$?

I understand that in linear regression the errors are assumed to be normally distributed, conditional on the predicted value of y. Then we look at the residuals as a kind of proxy for the errors. ...
1
vote
0answers
29 views
+50

Alignment / matching problem with groups

I have two data sets (base and to_match), each with 10 individuals, grouped in 2 classes. Each individual is described by a set ...