Questions tagged [experiment-design]

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

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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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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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D-Optimal Criteria Vs Differential Shannon Entropy

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 hasn't been rigorously answered. My ...
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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 ...
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Explaining conditioning number in statistics to non-statisticians

I work these days as a statistician and a lot of what I do is evaluating design of experiments; I started this job less than a year ago, after getting a PhD in mathematical statistics. I remember once ...
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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 ...
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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 ...
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1 answer
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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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Questionnaire design for linear regression

I am trying to conduct a research on brand preferences and I am trying to analyze regression equation i.e. which factors affects the consumer preferences (dependent factor) and other determined ...
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5 votes
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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 ...
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Statistically, is it effective to design exams to get harder as you answer correctly?

I think we have all taken exams where as you answer more questions correctly, the exam gets harder. Intuitively, this is obvious why...If an IQ test had questions for 3rd graders, everyone would get ...
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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 ...
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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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Reference for flawed randomized controlled trial

For a seminar, I am preparing an overview of advantages and shortcomings of randomized control trials (RCT; one shortcoming is, for example, often a limited external validity). To illustrate ...
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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 ...
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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, ...
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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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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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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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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?
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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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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 ...
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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 ...
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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 ...
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4 votes
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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: ...
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3 votes
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is ab test valid for concluding causal relation, when analysis unit differs from randomization unit?

In a typical A/B test, the randomization unit is user level, sometimes the analysis unit may be page/visit level, like a cluster randomization experiment. In this situation, the iid assumption doesn't ...
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102 views

Photo attractiveness rating experiment: significance and effect size

I'm a photographer working on a personal project where I experimentally test dating photo advice. I take photos of people under different conditions, changing one variable while keeping others ...
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3 votes
2 answers
60 views

Power analysis for unknown experiment duration

How would I do a power analysis if I do not know how long we want to run the study? I want to use analysis to inform how long I want to run the experiment based on how long it will take to gather the ...
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3 votes
1 answer
318 views

What are the advantages/disadvantages of design of experiments (DoE) versus stochastic optimization methods

I am working in a project to assist an experimental team in optimizing reaction conditions. The problem involves a large number of dimensions, i.e. 30+ reactants which we are trying out different ...
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3 votes
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38 views

Choosing training data inputs to optimize approximation

Suppose you have a smooth function $f^*:D_1 \times D_2\rightarrow\mathbb{R}$ that you observe with error as $f$ such that $$f(x,y)=f^*(x,y)+\epsilon$$ where $\epsilon$ has zero expectation (you can ...
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3 votes
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How to deal with an incompletely randomized experiment and LMM?

The Experiment I am investigating if there are significant differences in crop-yield between the systems (1-6). The experiment I am working on is nine years old and can be seen as a partially ...
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3 votes
0 answers
135 views

Two-way ANOVA/GLM for 2x3 incomplete factorial design

I am designing a within-group study with two factors (fixed novelty, levels: old, new; and indexical novelty, levels: veridical, statistical, new; so a 2x3). Now, ideally, I would just cross these ...
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3 votes
1 answer
81 views

Causal inference method for analyzing randomized control trial with covariates / pre intervention observations

I've got a seemingly easy situation, which turns out to be a little more complex than originally thought. Here's the Setup: We have a randomized controlled trial. Test and Control groups are the same ...
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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 ...
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3 votes
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91 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 ...
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3 votes
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39 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 ...
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3 votes
1 answer
61 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 ...
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3 votes
2 answers
478 views

Bayesian A/B test analysis for non-binary actions

When analyzing experiments with binary action (for example, will a user convert or not), then Beta-Binomial distribution is apt for that. For example, to model Click Through Rate (CTR): ...
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3 votes
0 answers
129 views

Why there is no agrement on power / sample size for factorial repeated measures design?

I'm not really sure to what degree this is a statistical question but thought this might be the best place to start. If my questions prove only my ignorance please vote it down and I'll delete the ...
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3 votes
0 answers
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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 ...
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3 votes
1 answer
141 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 ...
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3 votes
0 answers
28 views

When designing an experiment, when is it worth duplicating runs to improve error estimates?

In reading about response surface modeling, I learned about the central composite design, and how repeated center points have the following three results: able to fit/model quadratic factor ...
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3 votes
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240 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 ...
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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 ...
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Box-Behnken vs Central Composite Design

So, I want to use either a Box-Behnken (BB) or a (circumscribed) Central Composite Design (CCD) for my 3-factor Response Surface design of experiments (DoE) and to build a linear regression model. I ...
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3 votes
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302 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 ...
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3 votes
0 answers
878 views

Repeated measures on split plot design with blocking

This is the first time I'm posting a question here. I have regularly been using the questions and answers here as example solutions for my problems, and searching has always helped me figure things ...
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What would be a proper statistical test for multiple models and model selection?

Suppose I have a data set of N observations (n = 1...N) for out-of-sample estimation and values of ($y_n$). I have also ...
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3 votes
0 answers
41 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 ...
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3 votes
0 answers
911 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 ...
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