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Questions tagged [blocking]

In the design of experiments, blocking refers to grouping similar experimental units together in groups ("blocks"). Comparing treatments based on within-block differences reduces the influence of extraneous variables, thus increasing power.

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Usefulness of Latin Square Design

I want to understand the usefulness of the Latin Square Design. Suppose there are two block factors, each with three blocks. There are three experimental groups: A, B, C. One realization of the Latin ...
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Why can't interaction be measured with a complete block design? [duplicate]

I am struggling to understand why interaction cannot be measured in a CBD. While many sources say it is because there is only one observation per block/treatment combination, could you not compare the ...
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Fitting Log Logistic 4 parameter Mixed Model

I have a set of experimental growth data where I exposed a group of animals to increasing concentrations of multiple toxicants. Two toxicants were run at a time in batches due to material ...
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Random effects - Determining mixed model with multiple random effects?

I'm currently trying to find the best way to analyze whether habitat restoration treatments affect arthropod family richness on a sand dune ecosystem and am having trouble determining the random ...
mgaytan's user avatar
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Randomized blocking design and Mixed Models

I am developing a research project where we are evaluating the growth of seedlings. The plots are distributed in an open greenhouse and some environmental parameters vary according to their position. ...
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Appropriate design for two experimental conditions and incomplete blocking

I'm planning to perform an experiment in which I will be assessing the role of two experimental variables (A: 6 levels, B: 4 levels) on a defined outcome which, however, might be affected by external ...
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How should I analyse this experiment with two blocking factors

In this experiment, a machine is used to compare the wear resistance of 4 different types of rubber-coated fabric (variable mat coded A, B, C and D). To do this, ...
Vivek Sharma's user avatar
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What is a Randomized Complete Block Design. How do we create one and analyze it?

I have been reading about experimental design, and Randomized Complete Block designs (RCBD) in particular and I have a few queries. What exactly is a randomized complete block design ? Is there a ...
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Treatment of blocking variables in LASSO regression

By reviewing the existing relevant questions I could not find the answer to this specific question. I have created blocking variables with the one-hot method (n - 1 binary variables for n categorical ...
Oculatus's user avatar
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Does this design indeed raise concerns about pseudoreplication?

We want to test the effect of dietary supplement on two groups of cows (randomized and controlled for starting weight and age). Group 1 (6 cattle) receives supplement 1 and group 2 (6 cattle) receives ...
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Lock predictors subset before final model building

Let assume that we have a training test and a test set with unseen data. I perform monte carlo cross valitation on training set to tune hyper-parameters. The question is related to feature selection. ...
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Can I test blocking effect in non parametric test

I have two replicates (tanks) for 4 treatments (hyperthermia, hypoxia, combined hyperthermia and hypoxia, and control), with 10 randomly assigned organisms for each tank. The response variable is non-...
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Experimental design with two factorial treatment and blocks of the treatment combination

I am going to do an experiment with planting seeds involving 2 factorial treatments. There are 4 families of seeds: F1, F2, F3, F4 and 3 foliar seed treatments: T1, T2, T3. There will be 160 seeds for ...
Sylvia Anderson's user avatar
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To pool controls or not?

I have a data set containing measurements from cells that have had 200 different perturbations applied to them. Each perturbation has been applied in duplicate. Because there are so many perturbations,...
Ian Sudbery's user avatar
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1 answer
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Understanding the advantages of CRD experiments

I am self studying an introductory course on Designed Experiments and have come across the notion of a Completely Randomised Design (CRD) defined as follows: Completely Randomised Design: the ...
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Relationship between blocks, factors and treatments

I have recently began studying a course on Designed Experiments and am having some trouble understanding some of the terminology. I've looked at some other answers on the site and I think that I am ...
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Between subject design, spread over multiple days

We have a between subjects design, testing for the impact of aesthetics on occupant satisfaction. Intervention is carpets vs no carpets. The people participating in each leg (intervention vs control) ...
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Split-plot design analysis by Linear Mixed Models in R

I am trying to analyse data from a Split-Plot experiment by Linear Mixed Models with lme4 in R. The design consists of a whole-plot factor and two split-plot factors (see attached layout). Whole-plot ...
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Blocking Design

Ran an experiment whereby I had a factor of 5 different levels on a plant cultivar. A wide range of responses were recorded. Due to the layout of the room, I quickly realised that blocking was ...
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Necessary and sufficient condition for existence of balanced incomplete block design

State and prove the necessary and sufficient condition for an incomplete block design to be balanced A balanced incomplete block design (BIBD) is an incomplete block design in which b blocks have ...
simran's user avatar
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Difference between blocking and split plot-design?

What is the difference between blocking in an experiment design and a split plot design?
Ben's user avatar
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Balanced incomplete block design - randomizing treatment order

In a balanced incomplete block (BIB) design, what is the best way to ensure each treatment appears in all positions/orders? Should I randomize treatment order within each block, so that participants ...
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Design of Experiment for one factor in R [closed]

Is there an package to design an experiment with a single factor, potentially with multiple levels? I want to know how a certain voltage depends on temperature and for that I initially planned to ...
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Possibility of non-binary balanced incomplete block design

Balanced Incomplete Block Design (BIBD) is defined to be a block design which is proper, equireplicate, incomplete and binary such that every distinct pair of treatments appear together $\lambda$ ...
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Blocking in $3^2$ fractional replicated design of experiments

I'm new to design of experiments and I'm planning an experiment which involves 2 factors at 3 levels ($3^2$ design). I'm using 3 levels as I think that there will be some non linearity, but I cannot ...
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How to calculate how many levels of nuisance factor I need for a desired power level in my experiment

I have a nuisance factor that introduces a lot of variation in my data. I want to know how many levels of this factor I need to include in my blocked design to get a power level of, say, 90%. As an ...
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Unbiased Estimator for Mean Response to Treatment

$\newcommand{\eps}{\varepsilon}\newcommand{\szdp}[1]{\!\left(#1\right)}$ Problem Statement: Consider the following model for the responses measured in a randomized block design containing $b$ blocks ...
Adrian Keister's user avatar
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Why is it acceptable to use the Sum of Squares of an Interaction as the Sum of Squares Error in a Randomized Complete Block Design?

Take for example the RCB design [Y = I + B + F + E], where... Y is the response I is the overall intercept B is a blocking factor with two levels F is a treatment factor with two levels E represents ...
Chris Science's user avatar
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How to analyze a randomized complete block design (block, plot, year) when assumptions of normality and heteroscedasticity are violated?

How do you analyze a randomized complete block design (6 plots within 4 blocks, data collected over three years) when assumptions of normality and heteroscedasticity are violated? Is this correct? Use ...
user333304's user avatar
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Is it possible to conduct meta-analysis for interaction between two continuous variables

all. I have conducted four studies to examine an 2-way interaction predicting a continuous outcome variable from a continuous independent variables and a continuous moderator. So everything is ...
Frostioe's user avatar
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One factor with two levels with random group effect

I'm testing the hypothesis: prey exposed to the chemical cues of a predator will have lower feeding rates than prey feeding without predator chemical cues. In this simple food chain the top predator ...
leigh24's user avatar
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ANOVA with blocking question

An ANOVA analysis is done on the quality of pizza in two settings: pan vs. no pan while blocking on pizza brands, one brand vs. the other while blocking on using a pan or not. Will the F-statistics ...
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Is it acceptable to remove a block of data from an experiment due to outliers

I performed an analysis a while ago, and the experiment was blocked for production day (3 different production days). Two of the production days had terrible outliers, and after looking at the Cook's ...
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Ex-post grouping blocks, when analyzing blocked randomization experiment, to avoid $N_b=1$ blocks

In an experiment I conducted, randomization was stratified geographically and then blocked by the baseline outcome variable, $x$. That is, within each strata, $s$, I grouped observations into blocks, $...
LucasMation's user avatar
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3 Treatment Agronomic Experiment: Latin Square or Randomized Complete Block Design with 4 replicates?

I need help with designing an experiment. Suppose I am testing 2 fertility programs against a control in Lettuce, for a total of 3 groups (Program A, Program B, and Untreated Control). Let's assume ...
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Treatment combinations in different blocks for a $2^6$ design with partial confounding

Let us consider a $2^6$ design in 8 blocks with ABCD, BCE and ADEF as independent effects are chosen to be confounded with blocks. Q.1 $\:$ Write down the treatment combinations in the principal ...
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Change parameters block-wise in experiment design?

Is it possible to generate an experiment design which changes a parameter block-wise? To be more precise what I would like to do: Run an experiment with a certain parameter (humidity) fixed which is ...
Ben's user avatar
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3 votes
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Block design or completely randomized?

I have 5 conditions in my experiment: A,B,C,D,E and my sample size is 200 subjects. I want to have 40 subjects per condition, so I assign a condition to a person randomly without replacement. E.g. ...
Maria's user avatar
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Experimental Design Problem with Goofy Constraints

I am having trouble designing an experiment. I will give a hypothetical example that shares the main features of my actual problem. Suppose there are: $M$ meadows, indexed by $m={1,...,M}$, where $M \...
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The treatments are collectively not significant but one of the treatment is significant

I am confused to interpret this kind of data. The Avg_Treatment is collectively not significant since the P-value is 0.094, bigger than the significance level 0.05....
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3 answers
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ANOVA complete block design, more units per block than treatments

I would like to design a randomized complete block design experiment (RCBD). Let's say I have 3 treatments and 10 logical groupings of my experimental units (EUs) which are the blocks. If each of my ...
Alex's user avatar
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Is it possible to affirm there is pseudoreplication in a design without making assumption on variable importance?

this is quite an abstract question, but I am trying to learn more of the basics in pseudoreplication. Pseudo replication is defined by Hurlbert (1984) as: Pseudoreplication may be defined , in ...
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Does RCBD tend to increase the F value compared to the one way ANOVA?

I thought that the RCBD model accounts for the variation from different factors, and so when we use ANOVA, the treatment effect gets "muddled up". Hence our F value in the RCBD model is higher than ...
Suzee's user avatar
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Randomised Block Design

Suppose the response of three different treatments, $A$, $B$ and $C$ are measured in two different hospitals of a country. The data are given below. My question is: so far I understand it is a ...
user149054's user avatar
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Determining standard error of the mean from a correlated, stationary time series using known autocorrelation without block averaging

I'd like to determine the SEM of measurements taken from a stationary time series. SEM calculation using all measurements isn't accurate because adjacent measurements may be highly correlated, so the ...
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What statistical test (using R) can reveal relationships between 5 factors in randomized block design?

I'm at a loss as to how I can efficiently obtain p-values in R for the relationships I am interested in exploring in my dataset. Here is a picture summarizing the block design. Various response ...
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Analysis of incomplete block design and block-level attributes

I am working in a system where experimental treatments are necessarily associated with specific blocks (a complete design is not possible) and am looking for guidance on valid model specification. ...
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Randomized Complete Block Design with Replicates

A horticulturalist conducted a nitrogen fertility experiment for lettuce in a randomized complete block design. Five rates of ammonium nitrate treatments (0, 50, 100, 150 and 250 lb/acre) were ...
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Block-treatment interaction for Randomized Block Design (RCBD) and Generalized Random Block Design (GRBD)

I understand that RCBD experiments usually only contain one observation per cell (block-treatment combination). Also, there should be no interaction between the treatments and blocks. In GRBD, there ...
Fatima A's user avatar
4 votes
1 answer
258 views

Do I want a mixed model for fractional factorial designs?

I have created a D-efficient fractional factorial design of 48 combinations from a total of 192 possible combinations (4x2x2x3x2x2). For the experiment, I plan to have 4 runs in 12 blocks and 40 ...
T-Porsch's user avatar