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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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 reps. They have been either conventionally or organically managed ...
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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 ...
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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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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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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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28 views

Paired $t$-test with multiple values

With the following data, I believe the difference in performance between two athletes can be measured with a (one- or two-sided) paired $t$-test: ...
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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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What should be the layout of blocks in an agricultural CRBD experiment; by definition in a file or not?

I was having a discussion with a coworker concerning the layout of the blocks in an greenhouse experiment. I assumed that the main purpose of blocks was best served if the variation between blocks ...
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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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Randomized blocking “after the fact”

I have 5 treatments that I'm going to randomly assign to visitors to my website. I'll have 10,000 or more visitors. Is it statistically valid to analyze the results based on visitor characteristics ...
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Specifying ANOVA with incomplete block design (R)

I have experimental data of individual sizes (continuous) as a function of two categorical variables (A and B) each with 2 levels (1 and 2), along with a control treatment. Each treatment condition ...
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Restricting block size in a factorial experiment

I have the following: It has been decided to run an experiment involving 2 replicates of a $2^4$ factorial with factors coded A, B, C & D. However, block size is restricted to 8 I'm not sure ...
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standardising independent and dependent variables within blocks?

I have data from a randomised blocked experiment testing the effect of different crops on weeds. Each treatment was replicated in one plot in each of three blocks, on two farms, in two years (but NOT ...
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What makes a block a block

In multivariate analysis involve analysing different data sets of the same individuals, sometimes it is called integration or multi-block analysis. However I can't find how are these dataset defined: ...
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Coefficients in a Randomized Block Design

If, for example, I am running a GLM with Poisson distribution (it could be any distribution) and I have a Randomized Block Design (RBD) [Note: I dont wanna run a GLMM just to put the blocks as a ...
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What statistical test would be best for before and after comparisons of multiple similar groups?

I can't exactly give the problem I'm working on but I will give a sensible example of how it looks: I have 4 groups of people: diabetes, depression, schizophrenia, dementia, notice how a person with ...
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What statistical test should I use to compare before and after drug treatment in a group of 8 subjects?

I have a group of 8 subjects. For each subject I measure their heart rate 30,20, and 10 min before and after they take a drug. I then average the heart rate measurements in each subject to get one ...
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How Is This Design a Randomized Complete Block Design?

I recently started learning about one-way ANOVA, multiple comparisons, and contrasts. At the moment, I have an introductory-level knowledge of these concepts. I'm analysing an experiment that ...
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Best way to do block randomisation with covariates?

I have a set of $n$ objects for an experiment and I want to randomise them into a control group and treatment group with fixed sizes. I would like to use block randomisation to balance covariates, in ...
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CRBD design question about difference of means

I have the following code: ...
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Applying a mixed effect model on autocorrelated nested data?

I’m having a hard time figuring out what type of model I should use to analyse data with a rather complexe design. Experimental goal and protocol: The goal is to study the effect of beehive color ...
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SAS code to check normality assumption of random effect on blocks in a RCBD

I have a model with 2 factors of treatment and a block effect that the block is a random effect. for checking the assumption I need to check the normality, equality and independency of the variance of ...
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Is there a generalisation of Wilcoxcon paired sign-rank test to compare more than two connected samples?

I have a table where columns denote customer, row-supplier, cell- total amount of items, sold by supplier to customer. I have a zero hypothesis(H0) about random choise of customers and H1 hypothesis(...
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Sum of Squares in Randomized Complete Block design

I'm interested in the Randomized Complete Block design (RCB) with three treatments, which I call $A$, $B$, and $C$, and four blocks ($b=4$): \begin{align} \textrm{block 1: } (y_{A,1}; y_{C,1}; y_{B,...
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Difference between one-way ANOVA with randomised blocks and nested ANOVA?

I'm doing a biology course and am very inexperienced with stats. My supervisor recommended that I go away and try an ANOVA with block design, but I hadn't heard of this. Having looked up about it, I ...
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How to generate a Randomized Complete Block Design?

I'm studying agriculture and I'm looking for answers concerning one of my problem. I have to implement a randomized complete block design and I would like to generate it with R. I've found some ...
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Comparing two metrics from the same plot. Should I use a two-way ANOVA?

I have the following design. In each sampling plot, I measure food in four patches (BD, BF, OD, OF). From those I calculated preference for B trays and for D trays. So for every sampling plot I have ...
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Incomplete block design analysis / design with R

I have a few questions that arose when working on designing the following experiment. The numbers and variable levels are all made up for examples sake. I want to test the effect of incubation period ...
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What is the meaning of “each treatment ” in BIBD?

(I am restating the question again in a more clear manner, as it was not clearly written last time) My doubt is regarding Balanced Incomplete Block Design (BIBD) Consider the following design with ...
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Question regarding a factorial design and the main effect of one of its factor

Suppose we consider the following $2^4$ factorial design with factors A, B, C and D in the usual order. $Block1 - (0,0,0,0),(0,1,0,1),(1,0,1,0),(1,1,1,1),(1,1,0,1),(0,0,1,0).$ $Block2 - (0,0,1,1),(...
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Is there an experimental design that tests three different factors?

I am planning on performing data collection on subjects to see how well certain wearable products perform. Let's call the products A, B, and C. The goal is to see if any of the products performs more ...
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466 views

Examples of connected designs in DOE

I want to understand connectedness in block designs , I know this about connectedness : a design is said to be disconnected if we are able to create two separate groups such that they do not contain ...
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Is it appropriate to consider the interactions between blocking and fixed factors

If you have an experiment with multiple treatments (lets say 4 fixed factors with varying levels each) and you use a randomized complete block design, is it appropriate to consider the interactions ...
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I think this is a RCB design…but I'm not sure how to analyze it

Edit: Clarified by including the overall question I need help with and the experimental questions of my project. Overall question to you (ie, what I need help with): Does this experiment sound like a ...
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Non significant nuisance factor and interaction

I had this problem,it simply to see that the variable "Day" can be viewed as nuisance factor.This is my anova table: ...
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How to combine in a (fractional) factorial design model the blocking effect with a treatment (package planor)

For my greenhouse experiment with potted trees, I am planing a fractional factorial design. The experiment has six factors (treatments) each with two factor-levels, and I want to use a model/package, ...
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Is this a Blocked design ANOVA, two way anova, or ANCOVA

I am running ANOVA to test for a significant effect for some data, and a grad student said I should run an ANOVA test formatted like this in R to test for significance: ...
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Comparing Power of SRS to Block Randomization

I am trying to figure out how to run/analyze a block randomized experiment in the following situation, and to figure out how much of an improvement I would get over simple random sampling: Suppose I ...
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Does the blocking factor confound the fixed effect in my model?

I have data from an experiment with the following design: 11 blocks within a forest along an elevational gradient Within each block, three treatment plots (control, low and high treatment) with ...
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Using blocking in propensity score analysis?

I'm considering blocking my analysis dataset on one or two key variables prior to a standard sub-classification propensity score analysis. For example, if my dataset (which contains member level pre- ...
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Relation between Stratify Sampling and Blocking

In experiment, if you know before that an attribute $X$ may affect the treatment effect, so you could do stratify sampling from your target population, e.g., if $X$ is weight, then you could divide ...
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Randomized Complete Block design?Pair-T?

I would like to compare the performance of m different methods. So I run each of them k times on n data sets. I run multiple times because there is a little randomness in each method; i.e. repeated ...
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2^3 Factorial design in Yates' notation

Consider a 2^3 factorial design lay out in 2 bocks,each of size 4, as follows Block I {1,a,b,c} Block II {ab,ac,bc,abc} Here,the treatments combinations are written in Yates’ notation.Then which of ...
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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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Why is blocking necessary in experimental design if we already perform random assignment?

I am going through the first part of the Duke statistics course on Coursera, and the concept of blocking in experimental design comes up. If I understand correctly, blocking refers to separating ...