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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difference between stratification and blocking in experimental design

What is the difference between stratification and blocking in experimental design(or randomized control trial)? Blocking is to obtain homogeneity in a controlled factor. However, I can block more than ...
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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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Doing repeated measure with blocking design

for this study which analysis do you suggest? repeated measure or blocking design? I have 6 subject, to compare effect of a drug administered in four dose levels. Dose 0 we used control. two days wash ...
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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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Do I have to account for repeated measures in my mixed model (lmer) in R?

The experimental design looks like this: It's an alpha-Design with several genotypes and with 3 replications. Each replication is divided in several incomplete blocks. I took a measurement (obs) on ...
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Block Randomization but no. of subjects not a multiple

I have a question on how to do block randomization. I am running an experiment with 5 conditions (4T and 1 Control), and I would like my subjects to be as evenly distributed as possible. For example, ...
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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 ...
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How to handle randomized block design with missing data?

I am trying to answer the following question. I think parts (a) and (b) are relatively straightforward so I won't clutter up this post by showing my work. However I am completely unfamiliar with (c). ...
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How to calculate pooled variance when Block(replicates) exists?

Here is one data I generate by R ...
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How does two-step randomization affect the variance partitioning in an ANOVA?

I am trying to understand how multi-step randomization affects ANOVA results. For example, I can think of a pair of experiments, both with 2 crossed factors, FxG. In the first experiment, shown on ...
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Randomized block design in R

I have a medical data from 5 different places. I was wondering how I could analysis the following question: Does using treatment increase mortality risk relative to using placebo based on conditions ...
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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 ...
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Mean Sum of squared Error in TWO WAY ANOVA

This is a randomised block design with each b blocks and m conditions. Each block-condition group has n data points making a total of $n\times m \times b $ data points $Y_{ijk} = \mu + T_j+w_k+\...
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In an RCBD where samples are taken from different sites then allocated to treatments: block first in field or lab?

I am a soil scientist, designing an incubation experiment. I will sample soil from adjacent fields under different management. In the lab, I will subject the soils to different stresses and monitor ...
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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 ...
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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 ...
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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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Does this "transpose block bootstrap" make any sense?

Say we have the following data Say we are concerned with a linear regression model that is $\boldsymbol{y} = \alpha + \boldsymbol{d} \beta + \boldsymbol{u}$ and that we are interested in the ...
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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, $...
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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 ...
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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. ...
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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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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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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appropriate error term for a randomized complete block design, possible split plot in time, with subsamples (in SAS PROC MIXED))

I am analyzing the results of an agricultural experiment, as follows: Plots are laid out in a randomized complete block design with 3 replications. They have been either conventionally or organically ...
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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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Identifying treatments with non-zero effects

I have a complete block design experiment with a large number of treatments were I am trying to identify treatments with significant effects (positive or negative). I know the Friedman/Durbin tests ...
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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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4 x 4 x 4 Factorial Design or 4 x 4 Factorial with Blocking?

Problem here: https://imgur.com/Nl8AWie I was thinking that this problem might just be a 3-factor factorial design, since obviously the ad campaign and packaging are factors (we're interested in ...
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4 votes
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Crew selection: ranking rowers by letting them race against each other

Seat selection is a common practice in competitive rowing and I would be curious about more solid statistical underpinnings: there are more rowers in a team than the 8 seats in the crew boat. So the ...
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1 vote
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Randomized Block Design Models

I have been asked to fit the following models in R: The models are based on this data: I know the mediums are the blocks and the units of the active ingredient are the treatments. I understand how ...
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When to use blocks?

I am currently studying Random Complete Block Designs (RCBD) and I would like to ask a question. I cam across an example where we were able to conclude with the RCBD as significant, but regular ANOVA ...
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Test for yield and disease incidence in block design

I need to analyse a set of data coming from an agricultural experiment, with the intention of assessing the incidence of a certain disease in potatoes under three different treatments (plus blank). I'...
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Incomplete block design analysis

I have 4 treatments (6m, 12m, 24m, 40m) in 3 blocks, but all treatments are not replicated in these blocks: 6m, 12m, 24m are in Blk1 and Blk2 and Blk3 consist of only 34m (control plot) and 6m. How ...
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In marketing experiment, can we determine the effect customer state has on response?

We have the goal of determining whether an email campaign has an impact on the amount of product that customers purchase. We have customers from several states but much more from some states than ...
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defining arbitrary blocks

In an experiment with 4 treatments (a, b, c, d) and 3 observation per treatment, is it valid or desirable to impose $n$ blocks on the design. That is there is nothing that distinguishes the blocks. ...
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