All Questions
Tagged with anova experiment-design
280 questions
0
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8
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Can MANCOVA be applied for the following parallel factorial trials?
Good morning everyone, I have a question about the validity of MANCOVA for a project. I have a factorial experiment to optimize removal efficiency "Y", considering two factors (velocity &...
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1
vote
0
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29
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Nested design with fixed and random effects: Is my R model correct?
I am trying to analyze a nested experimental design in R, but I am unsure whether I am approaching it correctly. I have a following data:
Set
Sample
Repet.
Response
1
1
1
y1
1
1
2
y2
1
2
1
y3
1
2
...
- 11
0
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0
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11
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Can I use only the block section of a center composite design for optimisation?
So I designed an experiment with 6 variables to run sequentially in a supposed closed environment automatically. However during the switch from different blocks, something went wrong and now only the ...
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1
vote
1
answer
41
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What's the main effect for a factor?
this is my first question on here. To add a little context: I'm studying the design of experiments and I'm having trouble with the part on the main effects of the factors. I understood that if you ...
- 11
0
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0
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28
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Dunnett's test for comparisons with Control - how to conduct ANOVA for 2 factors, as well as adjusting for different experimental designs?
From what I understand, before we conduct Dunnett's test for comparisons of treatments to a Control, we have to do ANOVA. However, for a 2-factor experiment, there seem to be a lot of problems to me.
...
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3
votes
1
answer
197
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Reduce the model sequentially
I was given an ANOVA table and asked to reduce the model sequentially.
I searched the online resources say: When reducing the model sequentially, you typically start by assessing the significance of ...
- 669
1
vote
1
answer
161
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How to code a lme, lmer, or glmer model for a split-plot design (ANOVA)?
I have a study where the initial height of seedlings were measured at year 0 and again 11 years after treatments were applied and a net change in height was recorded.
I have a split-plot design as ...
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2
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1
answer
76
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How to consider independent samples in a mixed-design experiment?
I collected data from an experiment with a mixed-design, specifically a 2x3x4 mixed-design, where the factors are populations (2 levels), conditions for the first population (3 levels), and conditions ...
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1
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0
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85
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What do you think of this analysis for a small dataset with a weird experimental design?
I have a very small dataset (n<30) that is divided in 3 groups: healthy controls, patients with condition A, and patients with condition B. I am going to do a lipidomics analysis of the samples, so ...
3
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2
answers
76
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How to construct the full interaction term for a 3-way ANOVA?
Say for the sake of the argument I have a 2x2x2 ANOVA on factors A, B, and C with levels (A1, A2), (B1, B2), and (C1, C2). Also, the design is fully balanced.
I have the following 8 groupings as a ...
- 133
2
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0
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108
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How to conduct repeated measures Anova when there are two within factors but I am only interested in the effect of one factor?
For example, if my experimental design requires the subjects to participate in two identical sessions at two different time points(factor 1). In each session, the subjects go through all three ...
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1
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0
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35
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Appropriate analysis for comparing treatment that is between groups to baseline collected within (multiple) groups [closed]
To help outline my question I will start with how this would normally be undertaken. Say this is animal study looking at the effects of a drug on withdrawal. The outcome in this case will be time ...
- 11
0
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0
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42
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How to best interpret factorial design results?
I am analysing data from a 2^3 factorial design in R. I am using blocking, and I was wondering if my reasoning is correct. I am testing reaction time in milliseconds with three factors (Type of test, ...
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0
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194
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Is there a function in R to give the lack of fit and pure error of an ANOVA completed on a half 2^k factorial with centre points?
I have a half fraction factorial experiment for four factors, meaning I have eight experiments that I conduct. I expect that some of the responses are quadratic and not linear, thus I included centre ...
1
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1
answer
54
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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 ...
1
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0
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29
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How to combine within-subject score for between analysis when there is no within ID
I was task with analyzing some within/between-subject data, but my current guess is that I have no way of analyzing a combined within-subject score since an identifier/ID is missing. Is there a ...
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1
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0
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37
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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) ...
- 23
2
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0
answers
37
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Whats the model of this experiment
$36$ blood samples are collected at random from a blood bank and $6$ samples are sent to $6$ laboratories for studies. The assignment of each sample to each laboratory is random.
A friend of mine told ...
1
vote
1
answer
81
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Experiment design - response variable is a sum over a period, low power
I would like to run a statistically rigorous experiment, similar to that of an E-commerce A/B test.
I want to create a checkerboard of time periods where I alternate between treatments A and B. ...
- 11
3
votes
3
answers
677
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What does the phrase "adjusted by" mean?
"Matching of one group with specific exposures or outcome with a
comparable group is frequently used in medical research to investigate
the association between exposure and outcome." Ref
...
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3
votes
1
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179
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What kind of study design is this and what kind of statistical analysis should be suitable?
I plan to conduct a study in which respondents will be asked to solve total 6 puzzles together.
Is there a specific study design (name) for this?
The scenario would be:
First, ...
1
vote
1
answer
1k
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How to do pairwise comparisons for Kruskal Wallis test?
If the null hypothesis in the Kruskal Wallis test is rejected, How can we perform pairwise comparisons? Can we apply Dunnett's Test for that?
- 11
2
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0
answers
29
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How to study the impact of time in a mixed-factorial design?
I ran a study to compare 2 different computer interfaces (say A and B) meant to be used in an unfamiliar environment.
I want to compare:
How much effort participants took to complete a certain task ...
1
vote
0
answers
54
views
What layout is this?
A fleet of electric vehicles are to be investigated for the mileage performance per
charge. Four vehicles have been chosen randomly from the fleet and four observations of miles were made for each ...
- 11
0
votes
2
answers
814
views
Two way ANOVA unbalanced and nested TYPE III. Significant results
I have an unbalanced design with nested factors. In particular, the nested factor is obesity, with levels: of obese and nonobese. The other factor is group: women with syndrome, control women, and ...
1
vote
1
answer
236
views
low sample size experimental design, t-test vs one way ANOVA
I'm designing a biological experiment wherein the sample size is very limited, as each sample is very hard to get. Moreover, I need to have 4 independent groups, each receiving a different treatment.
...
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1
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0
answers
168
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2x2 Repeated measures ANOVA gives DIFFERENT result in R and SPSS? (Same type of sums/data/analysis) Anyone know why?
Reposting this because I fixed the formatting to see if someone can actually provide a solution for this problem. I have a study design in which I am carrying out a 2x2 repeated measures ANOVA in ...
- 58
1
vote
0
answers
36
views
Suggestion Needed about Design Experiment
As a part of my coursework, I'm supposed to be designing an experiment for an online cab service provider to understand the following:
Whether letting the cab driver know the drop location of the ...
- 123
0
votes
1
answer
553
views
Analysis of design of experiments with binary response
Having a hard time determining the best way to analyze this DOE, as I'm generally used to outputs in a different format and with numeric responses.
I've essentially got 2 variables at 3 levels and a ...
0
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0
answers
70
views
Is it appropriate to use difference scores in this context?
I am trying to compare the level of rating accuracy of two groups of participants (say Sample A and B). The study design is as is: I asked a consumer panel to rate how much they liked three products. ...
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1
vote
1
answer
40
views
imbalanced experiment group design
I am trying to decide if I can use an univariate GLM model in SPSS with factors of cause, side and tool with the sample size distribution as below. Ideally, tool should be added as a random factor ...
- 21
1
vote
1
answer
59
views
In a 2-Factor Repeated Measures design, Why do the ANOVA Expected Mean Squares have the values that they do?
I am studying experiment design, and I am trying to understand why certain designs have the Expected Mean Squares that they do. Today, I want to ask about a particular design: the 2-Factor Repeated ...
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0
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0
answers
194
views
Using the IQR method to filter outliers in experimental research, by group or as a whole?
In my current dataset (results from a factorial ANOVA), I know I have outliers (due to qualitative comments participants wrote during an online experiment), thus I'd like to do a filtering process to ...
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0
votes
1
answer
168
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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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1
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0
answers
158
views
How do I write sum of squares and degrees of freedom for multiple Latin squares put together?
I have notes from my professor in which a Latin square model ($s$ treatments in an $s \times s$ square) is described as follows:
\begin{align*}
Y_{ijk} &= \mu + \alpha_i + \beta_j + \gamma_k + \...
- 601
0
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0
answers
145
views
How to choose the right analysis for a partially nested design?
I am not even sure if it is appropriate to call this scenario a partially nested design, but I settled for it for lack of a better term.
My design is similar to the following in terms of its overall ...
- 165
2
votes
1
answer
652
views
Deriving the expectation of SSE in randomized block design
I am trying to derive the expectation of the $\operatorname{SSE}$ in a randomized block design, $\mathbb{E}(\operatorname{SSE})$, with
$$\operatorname{SSE} = \sum_{i=1}^b \sum_{j=1}^k(y_{ij} - \...
- 51
0
votes
1
answer
143
views
ANOVA or T-test for multiple groups, each group with a set of observations?
Can someone please advise on which sort of experiment or test I should run for the following.
I want to know which messages would potentially resonate more within a population. I have conducted ...
- 3
-1
votes
1
answer
655
views
How do I derive the Sum of Squares sums for an arbitrary ANOVA?
I know it is possible to derive the Sums of Squares sums for a simple one-way CRD ANOVA. It is done by substituting the treatment factors into the total SS equation, then squaring, eliminating terms ...
- 403
2
votes
1
answer
272
views
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 ...
- 403
0
votes
0
answers
118
views
Analysis sense check: preregister planned contrasts which we wish to conduct even if associated ANOVA is nonsignificant?
I could use a sense check on my analysis plan for an experimental study which has not yet been run; I will preregister it once I am confident that it is reasonable. There are seven between-...
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1
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63
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Different ANOVAs per species for same variable; how to proceed if only some species hold non-normal data
I am conducting two-way ANOVAs to determine if plant height (mm) is affected by treatment (3 water regimes) in different growth medium types (2). I am also interested in the interactions that may ...
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2
votes
0
answers
53
views
How to do statistical analysis on continuous group? Multinomial regression?
I am looking for suggestions on statistical methods for the following study design.
We have one control group and four treatment groups of mice.
Sample size is 6 mice per group. The number of ...
- 1,499
0
votes
1
answer
43
views
Causality comes form experiment manipulation or statistical calculation?
It is known that "Regression can only imply correlation but not causality"
But whether a research can draw their variables to causality relationship is somewhat determined by whether the ...
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0
votes
1
answer
3k
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Two factor ANOVA with blocking
I am conducting an RCBD experiment in which I have Treatment A (with 5 levels) and Treatment B (two levels). It is also being done in 3 separate locations (3 blocks). My question is, how can I do the ...
- 3
2
votes
2
answers
475
views
Prove two orthogonal contrasts are statistically independent
Linear combination $C=\sum_{i=1}^{n} a_i \bar{X}_i$ is called a (estimated) contrast if $\sum_{i=1}^{n} a_i=0$. Two contrasts are called orthogonal if $\sum_{i=1}^{n} a_i b_i = 0$; simplest example ...
- 604
1
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2
answers
982
views
What statistical test is appropriate for a pretest/posttest experimental/control group study?
I thought this would be a relatively straightforward question, but I'm having difficulty finding a decisive answer. Let's say I'm planning to run a study to test the effectiveness of a new type of ...
0
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0
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60
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Ensuring that sequence of repeated trials does not bias result
Imagine the following experimental design:
You have four conditions, A,B,C and D, regarding an online platform. Conditions A,B,C have a different feature enabled that you want to compare and D has ...
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1
vote
1
answer
75
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Derive $E(MS_A)$ in design of experiments
Prove that
$$
E(MS_A) = E\left[\frac{SS_A}{a-1}\right] = \sigma^2 + \frac{bn \sum_{i=1}^{a} \tau_i^2}{a-1}.
$$
Context. In Design and Analysis of Experiments, suppose you're doing a factorial design ...
- 569
1
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0
answers
16
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Between or within subjects?
So I have a 2x3 design with two categorical IVs, one is Country, the other is Message type (type A, type B, and control).
I've found published studies with very similar design that do both in between ...
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