Questions tagged [experiment-design]

The study of how to structure an information-gathering exercise where variation is present.

622 questions with no upvoted or accepted answers
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12
votes
1answer
401 views

Are non-square latin hypercubes viable?

At https://github.com/OpenMDAO/OpenMDAO-Framework/issues/599 it is stated that non-square Latin Hypercube experimental design is not well defined (I assume that for higher dimensions that means ...
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0answers
4k views

AB test sample size calculation by hand

Evan Miller has created a well-known online AB test sample size calculator. For the sake of being able to program and modify this formula, I would like to know how to calculate sample size Evan Miller-...
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563 views

How good is an optimal design (DOE)?

I am looking at an experiment with 5 factors (4 numeric and one nominal) with three levels for each numeric and 2 levels for the nominal. Instead of the 162 runs, I am interested in a small design (30 ...
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203 views

Pooling samples — what are the effects

There is an experiment in which biological samples are taken for several treatments and a control. For each treatment, we have enough resources to evaluate 5 samples. Some researchers suggest (for ...
5
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49 views

Modification to Latin Square Design

I have an experiment where I am having participants rate the readability of 10 different texts. I have 37 participants and I would like them to rate the readability for 6 texts each so that each text ...
5
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0answers
301 views

Optimum approximate theory D-Optimal design

I am using optFederov, from package AlgDesign, to create D-Optimial designs. However, I am a bit confused on what measure to use as efficiency measure. I'd like to use D-Optimal but I don't know which ...
5
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262 views

Sample Space of Machine Learning Classification “Experiment”

If you're trying to classify some input, $\mathbf{x} \in \mathbb{R}^{n}$, to one of $d$ classes using a model with parameters, $\theta$, how are you supposed to think about the experiment of learning ...
5
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124 views

Help with designing the analysis of a radio telemetry study

I was wondering if there are any spatial ecologists out there who can provide some insight on the trouble I'm having with my Masters research. I am looking at the association a bat species to high ...
4
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0answers
56 views

D-Optimal Criteria Vs Differential Shannon Entropy

I want to understand how minimizing the determinant of the information matrix is equivalent to maximizing the differential Shannon entropy? A similar question was posted in Math SE but hasnt been ...
4
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1answer
46 views

Treatment interference (causal analysis)

I am doing research on students and their perception of their grades. Specifically, I want to do an experiment where students either (a) see their actual grades in a course (as a percentage) - the ...
4
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0answers
305 views

Analyse sensitivity of hyper-parameters of Machine Learning Models

I want to analyse how sensitive my non neural net machine learning models are to the choice of the different parameters. I am currently using grid search to tune the models. Is there any method that I ...
4
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0answers
86 views

an alternative allocation method for small RCTs?

stratification and minimization are two randomization options to achieve balance in terms of covariates or baselines in small RCTs. in recent years, researchers seem to have favoured minimization, ...
4
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1answer
36 views

Can you derive density from a sample that includes different quadrant sizes?

I wish to estimate the percentage covering of vegetation in an area 1 km long and 600 m wide. Within this area I have percentage cover of vegetation for 10 circles with 10 m diameter and percentage ...
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518 views

Handedness — Observational study vs. Experiment

Let's say your goal is to determine whether left handed people are more coordinated with their right hands than right handed people are with their left. You gather up 20 left-handed people and 20 ...
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162 views

Combinatorial Block Designs in Statistics

How are combinatorial designs such as BIBD and Steiner triple systems used in statistics in designs of experiments and hypothesis testing.
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156 views

Video Lectures on Design and Analysis of Experiments

Where can I find video lectures or tutorials on design and analysis of experiments? E.g. something similar in scope and depth to Montgomery's Design and Analysis of Experiments?
4
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0answers
125 views

How to design a 2-level fractional factorial experiment given some prior knowledge

We're designing a trial to test four factors (call them A, B, C and ...
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242 views

GLM experimental design issues for count data in landscape experiment

I am analyzing bird count data from surveys conducted each week (from Nov-April, when bird foraging most active near breeding cycle) for 6 years in 9 large experimental plots that are split amongst 3 ...
4
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0answers
285 views

Regression model with heteroskedasticity in both variables

I've been learning (lurking) from this site for a while and I finally have a question I haven't seen answered yet. I'm doing a flight test and trying to fit the resulting data to linear line. From a ...
4
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0answers
386 views

Independent t-tests and Technical Indicators: Voodoo, Axes, and Objectivity

First off, I'm not trying to crowd source a personal printing press (i.e., not doing this: "I'm using strategies $x$, $y$, $z$ in the stock market and..."). Instead, I'm looking for feedback on ...
3
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0answers
51 views

Extending external validation diagnostics to experiments with continuous treatment

Does the external validation diagnostic methods discussed in Stuart et al. (2011) (i.e., inverse propensity score weighted regressions) also apply to the experimental setting in which the treatment is ...
3
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0answers
36 views

Weighing toilet paper with an imprecise scale

A practical, topical problem: Consider a typical roll of toilet paper (TP) with perforated sheets of fairly uniform size, and suppose we're interested in the distribution of a sheet's weight $W$ but ...
3
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0answers
30 views

Intuition of the regression model under fixed design case (nonparametric regression)

Let $(x_1,Y_1), \dotsc, (x_n,Y_n)$ be a random sample from the regression model $$Y_t=m(x_t)+\epsilon_t.$$ When authors want to develop the asymptotic properties of the local linear estimator of $m$ ...
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70 views

ANOVA/ANCOVA - how to analyse

In a basic research design where you want to test how some intervention (let's say our IV is 'drinking' with the categories water; sprite; and rum) affects some continuous measurement (let's say ...
3
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0answers
33 views

What's the rationale behind a normality test followed by a $t$-test?

Correct me if I'm wrong, but from my understanding, the standard procedure of testing whether data from an unknown source have a specific mean is to (a) perform a normality test to see if the data are ...
3
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1answer
29 views

GLMM in seed germination study

I have an experimental design measuring germination of a single species of tree under different treatments. The treatments include; cattle grazing and no cattle grazing and rodents and no rodents. The ...
3
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0answers
25 views

Advice for conducting the same experiment several times?

I'm very new to Bayesian statistics, but I've found myself in a situation where they might be able to help. I'll be running the same experiment repeatedly and analyzing the data every few months. The ...
3
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1answer
66 views

Single-cell RNA-seq: deep & few or shallow & many?

My lab does a lot of single-cell RNA-seq. Our goals are to find out what cell types are present, characterize their gene activity, and (if possible) understand how the different subpopulations are ...
3
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0answers
130 views

How should I specify my random effect when it is correlated to a fixed effect?

I want to perform a GLMM on my data in R using lme4. I have one response variable measured on more than 250 individuals. For each of those individuals, a ...
3
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0answers
1k views

T-test for regression coefficients obtained from Ridge, LASSO etc

In ordinary least squares, for example in an experimental design case, I obtain the regression coefficents by: $ \hat B = {({X^t}{X})}^{-1}X^ty$ Then, my null hypothesis for each coefficent is: $...
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0answers
302 views

Required size of control group for two-proportion z test

How do I determine, pre-experiment, the minimum size of a control group that would be needed to satisfy the requirements of a two-proportion z-test? $p_i=\frac{k_i}{n_i}$ is the proportion of ...
3
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248 views

True replicates or nested data ANOVA - only one experimental unit per condition

I'm in materials science. I have a fractional factorial experiment. I am investigating the main effect of various treatments on a measured response. The exact details are probably not needed to ...
3
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0answers
37 views

Between-subject comparison contains paired data

This is a difficult question to search for, so I apologize if it's been addressed elsewhere. If I am interested in the effect that weather (sunny/rainy) has on dog running speed, and I have running ...
3
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0answers
563 views

Experimental design when having continuous factors

I am studying about experimental design. I understand some of its general steps. I still have a small question: Can we apply experimental design when having continuous factors ? What I mean by a ...
3
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0answers
110 views

Allocation of design points in an experiment

I would like some hints with the following problem. Thanks for any help in advance. An experimenter wants to design an experiment for estimating the rate of change in a dependent variable Y as an ...
3
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0answers
73 views

$2^3$ Factorial Design conducted in a Latin Square Design

When does the situation occur to conduct a $2^3$ Factorial Design in a Latin Square Design? What would be the procedure of analyzing data of a $2^3$ Factorial Design conducted in a Latin Square ...
3
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0answers
97 views

Threshold for psychometric experiment with three (or more) possible choices

I'm running an experiment where subjects are viewing a stimulus, and they have to decide if the stimulus is brighter/darker/identical in respect to a standard image. Stimulus luminosity actually ...
3
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0answers
126 views

stepped wedge and additive intervention effects

Let's say we want to randomize 400 caregivers to a parenting intervention or a wait-list control group. But we also want to look at a program variation for a sub-sample of caregivers of children with ...
3
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0answers
263 views

Alpha inflation in the context of usability studies

In a hypothetical usability experiment, two interface changes are tested against a baseline. The interface changes are cumulative, i.e. variant B is an extension of A. We measure usability according ...
3
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0answers
417 views

How to deal with two time variables in panel data modelling using PLM package in R?

We have question regarding the analysis of panel data in R (plm) which was observed over two time scales. As way of a background, we have completed an economic experiment with a group of 6-8 ...
3
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0answers
338 views

Desirability approach to multiple optimization: drawbacks and alternatives

When fitting some relations $y_j=f_j(x_1, \ldots, x_p)+\epsilon_j$ between a multivariate response $y=(y_1, ..., y_k)$ and covariates $x_i$, a common problem is to determine for which values of the ...
3
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0answers
821 views

Split-split-split plot cross-over design… is this even possible?

I'm doing statistical analysis on a psychology study I ran a short while ago, and I'm starting to think that I've designed myself into a corner. In the study, we measured participants' pointing ...
3
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0answers
704 views

Cross validation using experimental design methods?

I have a question about using experimental design methods for cross validation in a non-conventional approach. I will use an illustration to explain the question. Imagine you have 100 time series ...
3
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0answers
407 views

How to test for differences in binary score data?

I have data from a human subject study that was setup as a 3x2 (system by task type) experiment, with 24 participants. Each participant completed 6 tasks in all, one using each of the 3 systems, and 2 ...
3
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0answers
456 views

How are Taguchi orthogonal arrays derived?

I am implementing statistical analysis in a C# program and am using the Taguchi Method to do it (the Taguchi arrays are about a 1/4th of the way down the page). The article in the above link mentions ...
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0answers
1k views

How to choose between nested or split-plot analysis of variance?

I am having serious problems understanding the type of design I have, I would appreciate any help you can give me to understand it: I have 324 data points, and four factors: ...
3
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0answers
278 views

Initial conditions of experimental units in Completely Randomized Design

Since I had no answer to the second part of this question I would like to ask it again providing some more infos I gathered in the meantime. Context We are designing a complete randomized trial in a ...
3
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0answers
141 views

Estimating parameters in a model with a periodic design parameter

We recently studied a model with a likelihood function of the form $$\Pr(d_i|\omega,t_i)=(1-d_i)+(2d_i-1)\cos^2(\omega t_i),$$ where $d_i\in\{0,1\}$, $\omega$ is an estimation parameter, and $t_i$ ...
3
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1answer
72 views

Biased estimator obtained by optimal experiment design

I am using a model-based approach to infer the parameters of a given system. Namely, I represent my system by a model $\mathcal{M}$ with parameters $\theta$. To estimate the true value of $\theta$, I ...
2
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0answers
9 views

De-aliasing two-factor interactions in a Plackett-Burman design

what I've got so far is a 2-level experiment design with 10 factors and 32 experiments, which is made of a resolution III Plackett-Burman design that I folded (complete foldover) so that it is a ...

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