Questions tagged [experiment-design]

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

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32 views

AB testing: test for nested variables

Sorry if my title is not clear, I'm very new to the random experiment field. I will start right off the bat with an example, hoping this clarifies things. Let's say I am a bank, which is looking ...
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Request on settling a “bar argument” about the law of large numbers

I'm currently in this argument with another person regarding whether or not it is possible to determine how much skill matters in a card game. My position is that determining this in general is ...
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How to test differences in importance of predictors across two experimental arms

I am interested in running a simple randomised longitudinal experiment, testing the effect of two different treatments on the outcome over time. Previous studies testing the same two treatments in ...
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Is there ever a right time to not use Bessel's Correction? [duplicate]

I can not find a clear explanation for when NOT to use Bessel's correction and use N instead of N-1. As I understand it, Bessel's correction would apply to things such as clinical trials, sampling ...
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The Relationship Between Experimental Design and Non-linearity

It's well known that the classical ANOVA (and ANCOVA) experimental design techniques can be expressed as linear regression (with categorical factors). However, linear regression is just that – it ...
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Experimental design to estimate the sample size

I've been newly introduced to Experimental Design and I am wondering about its possible connection with multivariate classification models. Is it possible to build a DoE able to predict which is the ...
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Full factorial experimental design ignoring time?

Can you use Full Factorial experimental design that ignores time as a co-variate when the correlation between time and one of the variables is significant? The experiment is as follows: I placed ...
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which experimental design better fits?

I test the effect of a plant dose on the abundance of a specific microbe, cultured in glass tube in vitro. The treatment consist of 5 doses (0, 1, 2, 3, 4). Each culture tube receives one of the dose ...
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149 views

Generative design - algorithms and sources

I have recently encountered the term "generative design" where a computer algorithm (usually with the help of Machine Learning) comes up with new designs that conform to a certain set of requirements. ...
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How to obtain a deglossed ANOVA for a three factorial design

So, I have run a three factorial design in R and got the ANOVA. But this ANOVA ever got two degrees of freedom for any main factor. In my book says: "The effects for every factor are considered, ...
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Intuition to the Resolution of a fractional factorial design

In design of experiments, is there an intuitive way to understand (and explain) the idea of the "resolution" of the design?
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Determining Profit for 150 different Treatments Types [closed]

My objective is to show which treatment or group of treatments was most successful at generating profit. I have a data.frame with about 7 million observations. Each of these observations could ...
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Leveling the field for a race competition

I'm not sure if this is really a statistics question, but I can't think of a more fitting Stack Exchange for it. My friends and I at work are having a competition to see who can decrease their one-...
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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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Help me name this quasi-experimental design

It is very simple I just need the name of it. One group during the pre-intervention period does not get the intervention, another group gets the intervention during the intervention period. Only 2 ...
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Experiment Design Question about period

I wanted to see the robustness of a machine learning model about retention. So I split the customers into level 1 - 3, the higher the level or scores , the higher the customers will improve its ...
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856 views

Good statistical software system for teaching response surface design?

I am looking for a good software system to teach students on response surface designs with. Few things I can think of are SAS Proc RSReg or SAS ADX. Is there any other software?
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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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Factorial experiment design with incompatible levels in IVs

Is it safe to run a Factorial ANOVA if you cannot collect data for some cells? Scenario: There are two independent variables, and one dependent variable. All independent variables are nominal: D (...
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What kind of design of experiment should I choose?

In my research, I want to study the early detection of learning problems of students in introductory programming courses. The first part of the study involves collecting their code, submitted to an ...
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Constrained design of experiments

I would like to conduct a 2-level fractional factorial experimental design on 8 factors. I used the FrF2 package in R to do so. I have capacity to do roughly 30 experiments, so I selected a resolution ...
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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 ...
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Experiment design: what's the difference between diff in diff and post-stratification?

what's the difference between diff in diff and post-stratification? When should we use diff in diff and when should we use post_stratification quasi experiment design?
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Which effects and which interactions are significant?

I'm performing an experiment with five main effects resp. 6-7 since these main effects influences are studied on 20 sensors (which can be grouped into 3 ...
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How to use multiple variables in a mixed model?

This is a follow up question to How to model this mixed model There, I asked how to model Resistance against carbon monoxide for ...
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Experimental Design with two treatment levels, random effects, and technical constraints

I'm trying to plan an experiment and the experimental design is giving me headaches because it's too complex to wrap my only-statistics-101-capable head around. Basically I want to subject plants of ...
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Blocking vs. Control

Am I thinking about this correctly? Blocking is something that is done on the experimental design level: If I'm not interested in the differences between school districts, I block by school district ...
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Statistical measure for the experiment(Siri vs keyboard)

I would like to ask about statistic measures in my experiment. I'm stuck on deciding measures for a few days, so I would really appreciate it if you help me with this. I did an usability experiment ...
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What is cross-lagged panel design?

The slides for my statistics lectures explain various experimental designs such as single-strata, cross-sectional and longitudinal. Unfortunately, the diagram for Cross-lagged Panel Design is very ...
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Factorial experiment in GLM model

I am reading some lecture notes on Factorial Experiments. Remark 6.1 In this course we only treat the linear model. The response variable may however be a (Poisson) count, or a (Binomial) number of ...
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389 views

How can I do a nested t-test?

I have data. Soil samples were taken from meadows and adjacent arable fields (see picture): There are always three samples per each opposing site. Since those 6 spatially conjoined sampling points ...
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Two-sample t test with before and after experiment data

I have data with the following columns: Person id, achievement before treatment, achievement after treatment (timewise) Each person is put into a control or treatment group. Because the data is ...
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Experimentation Time series - Find a control group whose mean follows closely the test group

I'm conducting an analysis from Jan to Dec where my test/treatment group is the combination of 5 stores with sales per month. The main objective is to find a control group of 10 stores over 150 ...
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the role of MDE in a/b test analysis

I have a question about the role of the minimum-detectable-difference (MDE) in power analysis before the experiment is run and in post-experiment analysis. To clarify: suppose I am testing the ...
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Does comparing percentiles of datasets with different sample sizes introduce bias?

Imagine an A/B test running on a website where we measure a metric like page load time. 90% of the page views are the 'control' and 10% of the views receive a special treatment that might affect the ...
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Advantages/disadvantages of fractional factorial design vs completely randomized design

I'm new to the design of experiments (DoE) and will be running a screening experiment to estimate the effect of a large number of binary independent variables (approximately 10) on a single continuous ...
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Why is ABC interaction completely confounded in this factorial experiment?

Consider a 2^3 factorial design layed out in 2 blocks ,with plot size 4, as follows Block I: {1,ab,ac,bc} Block II: {a,b,c,abc} This is replicated four times. abc is said to be completely confounded ...
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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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Two diagnostics tests over time

I have the following problem. I want to compare a self-diagnostics tool (questionnaire based) with a gold standard diagnostic tool. However, I have the following issues: 1- The gold standard is not ...
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Is there a non-arbitrary criterion to choose which points to use for interpolation?

Look at the image. I have to interpolate this experimental points with a voigt function to find the position of the center of the peak, I have to choose how many points and which points to use in the ...
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370 views

How to test for main effects in 2x2 factorial design with categorical outcome

The problem I have is as follows: I have a clinical trial based on 2x2 factorial design (four treatment combinations, balanced design)comparing treatment A with treatment B, where the primary outcome ...
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Find the orthogonal contrasts of the sources of variations in the following design

The question I know the condition of what an orthogonal contrast is: the dot product of their coefficients should be zero. Plus if we are given a set of contrasts, they are supposed to be mutually ...
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Data analysis of unbalanced study - Interaction techniques in virtual reality

I'm planning a study on interaction techniques in virtual reality. That means I want to compare the performance of the participants on different interaction forms (e.g. selecting objects with a ray or ...
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How to measure Sales lift for a campaign without experimental design?

I want to be able to calculate Sales Lift for a campaign conducted but prior to campaign no control group was established. So, I cannot measure the impact on Sales because of campaign to treatment ...
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Understanding the split plot

Can someone explain me the intuition behind the split plot? From what I understand, it is essentially restricted randomization. But I still do not quite understand it. Is there a resource or example ...
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Anova mixed- between and within

Hello my name is Francisco and i am having a big doubt in a statistical exercise in spss. that is i have two indpendent variables, each one with two level: sistem production: soil, substrate variaty:...
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Split plot design with psudo replicates

I am working on a project and need to analyze data that I know is an example of a split plot design but I am having trouble setting the model up correctly. Here's the situation: A bakery is testing ...
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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 ...
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maximum with response surface method

These are my data How do I determine the fitted model, gradient and maximum with response surface method? z1: low:50 high:180 z2: low:460 high:490 z3: low:60 high:80
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Calculate sample size (or experiment repetition no.) with unknown population

I am running an experiment and I would like what is a good method to calculate how many times I need to run an experiment, in other words, how many data points I will need to collect. The issue is ...

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