Experimental design, or design of experiments (DOE), is the design of any information-gathering exercises where variation is present. In statistics, controlled experiments are usually implied, which involve an "experimental group" and a "control group". In the design of experiments, the ...

learn more… | top users | synonyms (1)

1
vote
1answer
32 views

Which design is most appropriate?

I have data from an experiment testing a new treatment. Each subject has 4 data points, 2 of the new treatment and 2 of the control. It is like a paired analysis, but instead having 1 observation of ...
1
vote
0answers
22 views

multivariate analyses for incomplete factorial design

We have conducted a survey experiment with varying amounts of incentive (factor 1 = I1, I2, I3, I4, I5). The experiment was conducted stepwise in three subsequent studies (factor 2 = S1, S2, S3). ...
0
votes
0answers
15 views

Is there an equivalent to LHS for a discrete input space?

I was wondering if there is a method that is equivalent to Latin Hypercube Sampling when the input space you are trying to sample from are a finite discrete set of possible values. For example, if I ...
3
votes
1answer
40 views

Identifying the experimental unit

I have included a diagram of an experiment where cells are pooled from multiple animals, cells from the pool are then allocated to different treatments and a measurement is taken from each individual ...
0
votes
0answers
26 views

Correct use of Mixed model for random block design?

I have the following experimental design (random block design). Block with 4 Treatments (A, B, C, D) repeated at 4 different sites. Treatments were applied to individuals of different species (factor ...
1
vote
2answers
44 views

How to analyze this messy design?

I need to analyze a data-set, with a very messy design, I am not sure how. I will try to make it simple. A new kind of stitches was invented, and is tested vs. 2 old kind of stitches. I will call ...
0
votes
1answer
27 views

Multiple measurements of a single datapoint: what to do with variability?

I am interested in a general question about research design, but I will explain it on a specific example. Suppose I want to determine if one group of people has higher heart rate than the other ...
1
vote
0answers
31 views

Threshold for psychometric experiment with three (or more) possible choices

I'm running an experiment where subjects are viewing a stimulus, and they have to decide if the stimulus is brighter/darker/identical in respect to a standard image. Stimulus luminosity actually ...
1
vote
0answers
14 views

Logistic Regression and Design of experiment

I have seven factor and one response variable with 32 run and one replication i.e. 64 runs and I want to use logistics regression. I found in th analysis that 4 out 7 factors are significant. I want ...
2
votes
1answer
47 views

How to create a nearly orthogonal experimental design in R?

Does anyone know an R package for nearly orthogonal designs? I would like to create an experimental design, using 12 runs, up to 10 factors, and with mixed levels (e.g. a combination of 2 and 3 level ...
0
votes
0answers
10 views

counfounded batch effects in microarray dataset - can I do partial experiment redesign?

I'm working with a microarray data set where the batches are completely confounded treatment time, i.e. time t1 is all in batches b1 and b2, and time t2 is all in batches b3, b4, and b5. I know this ...
0
votes
0answers
7 views

Choice of dependent variable: Differencing or Controlling?

I was running some analysis where I suspect that a treatment $D$, has opposite effects on two variables $Y^A$ and $Y^B$. To show that, I was thinking about two strategies: 1. Differencing Running ...
1
vote
0answers
18 views

What are the statistical implications of assigning treatment and control in time series study under 2 different approaches?

I have a project wherein my group wants to measure the effect of counseling at-risk students on their academic outcomes. There are 1,000 students who will be enrolled during the current academic ...
0
votes
1answer
49 views

Experimental design and mixed models

I want to test effect of 3 PH on larval development. I would like to know what is the best experimental design and statistical analysis. We can only use 3 compartments of sea water, each one with a ...
1
vote
0answers
20 views

Sample size calculation for multilevel, longitudinal experiment

I'd be grateful for any advice about how to do a sample size calculation for the following design. We are interested in the impact of two variations of an intervention on hospital in-patients' ...
1
vote
1answer
33 views

Controled Factorial Experiment Design: which name or resource?

I'm designing an experiment which has to factors (A,B) with respectively 4 and 5 levels. Since this is quite a large amount, I figured I use a factorial design. However, it is unclear whether the ...
1
vote
0answers
22 views

Is it OK to take “Analysis of Variance in Experimental Design Models” Before a Regression Course?

I am a math major starting a MS program in statistics. I have taken an undergraduate sequence in stats (basics of distributions, estimation, hypothesis testing) but never a formal course in ...
-4
votes
1answer
34 views

How do I define generators in Minitab

How do I define generators in Minitab 16? I have an experiment design (DOE) with 5 factors and 2 generators. I entered D=ABC E=AC in the box of generators but it says only F through G ?
1
vote
1answer
37 views

Can I hypothesise an insignificant mediation? (Very basic stats)

This is for a simple psychology report. I was wondering if I could hypothesise an insignificant mediation. Eg: "...based on this research it is predicted that group identity is not a significant ...
1
vote
1answer
38 views

Establishing significance levels post-hoc

Proper frequentist procedure says that we should establish a sampling plan, statistical analysis and significance level before we start an experiment. We then report whether or not we reject H0 for ...
0
votes
0answers
17 views

Interpreting covariates in 2 by 2 MANCOVA

I am doing 2 by 2 MANCOVA with experimental data set. Followings are variables I used. DV1, DV2, IV1, IV2, and C1 where DV=dependent variable, IV=independent variable, and C=covariate. Consistent ...
1
vote
1answer
106 views

What type of Research Design?

In an experiment, 25 subjects (Group A) are assigned to play an adventure game (with audio and non-audio) while another 25 subjects (Group B) are assigned to play a strategy game (with audio and ...
0
votes
2answers
41 views

Difference between Research Design and Experimental Design

What is the difference between Research Design and Experimental Design? I can't see any difference. Both of them need to establish Causality. Both of them are the arrangement for collection and ...
1
vote
0answers
16 views

Type-1 Error of the Two-Stage Design

Background on Two-Stage Designs In clinical trials, we are often interested in the response rate $p$ for an experimental treatment. In a typical trial, we might expose $n$ patients to the treatment ...
1
vote
1answer
23 views

How to deal with outlier in the experiment

My question is related to this one. I'm working on an experiment involving transferring data between different locations all over the world via the Internet. As the Internet can be busy, sometimes it ...
1
vote
0answers
26 views

What's the sample size required to confirm that two treatments are identical?

Goal: Determine if a machine is defective Say I am going to give the same treatment to a group of people. I have a machine that will randomly split them into $2$ groups before giving the same ...
0
votes
0answers
14 views

Augmented split plot experimental design

I planned a field experiment with different genotypes according to an augmented design (check repeated entries plus unrepeated entries). Since I am testing a segregating population, each plot split ...
1
vote
1answer
60 views

What is the meaning of $A(B^2)$ interaction in a 3 level factorial with 2 factors $A$ and $B$, when the factors are qualitative?

I understand that when the factor is quantitative the $AB$ interaction can have a linear component and a quadratic component and so $AB^2$ makes sense there. But when we have qualitative elements how ...
1
vote
0answers
52 views

In an experiment w/binomial responses, some subjects gave the same answer for all trials. [How] can a Mixed Effects model (R's lmer) deal with this?

I recently ran a pilot of an experiment on Amazon's Mechanical Turk. In the experiment, participants read 5 items, and answered a yes/no question about each one. A between-participants factor was ...
3
votes
1answer
174 views

How big is “sufficient” sample size?

I am currently doing some tests with some specific parameter settings to characterize a process. I roughly remember that a widely used rule of thumb for lab tests and whatnot is a sample size of 5 or ...
2
votes
1answer
49 views

larger sample size or more accurate measurement?

This question is completely theoretical in the sense that I don't have any real data. Suppose I am designing a study, in which I will go measure N pairs of (X,Y), then the goal is to build a ...
0
votes
0answers
19 views

Split plot ANOVA or t-test

I did a study in which I wanted to see if a teaching intervention would have an effect on student learning. I nonrandomly divided students into two groups, a control and experimental group, and gave ...
2
votes
2answers
103 views

Designing Computer Science experiments (Hypotheses and errors?)

For my master thesis I want to set-up several experiments. One thing my professor has been complaining about is that most computer science experiments are lacking scientifically. To not fall into this ...
1
vote
0answers
54 views

Response-surface methodology vs. 3-level full-factorial [closed]

What is the difference between a Box-Behnken design, a central composite design and 3-level full-factorial design? What are the advantages or disadvantages of one design over the others?
0
votes
0answers
25 views

How to run regression on a Taguchi design?

I'm trying to run a regression analysis on a Taguchi design. I have five categorical control factors, one of them with two levels and the other four with three levels. I want to generate a regression ...
0
votes
0answers
21 views

What statistical tests to run given the design?

I have 3 research questions. 1) Does increased hyperlink insularity cause better user understanding? 2) Does increased hyperlink insularity cause better user perceived security? 3) Does increased ...
0
votes
1answer
69 views

analysis of alpha lattice design

Are there R some packages for analysis of alpha-lattice (0,1) designed experiment? My experiment includes two factors with two levels. The tests are performed in two replications with twenty blocks. ...
3
votes
1answer
98 views

Split plot with factorial design vs three way ANOVA

I have three site temperature types: cold, medium, and hot. This is a fixed effect - I am specifically am testing if temperature affects my response variable. I believe temperature type is my 'block'. ...
0
votes
1answer
24 views

categorical variables in factorial design

One dependent variable, One independent continuous variable and One independent categorical variable (two levels only). Factorial design is easy except I don't know how to add center points. I am ...
0
votes
1answer
61 views

Which Statistical Technique (ANCOVA or Taguchi methods) for this problem?

I have one qualitative factor (Treatments) and two uncontrollable factors, temperature and moisture, with one response variable. I'm confused whether I should use ANCOVA with temperature and moisture ...
1
vote
1answer
22 views

Alias Structure of one-fourth replicate of a $4^2$-Factorial Design with interaction $\text{A}{B}^3$ confounded

For finding the Alias of main effect A , i started as the following : $\text{A}$$\times$ $\text{A}{B}^3$$=\text{A}^2\text{B}^3={(\text{A}^2\text{B}^3})^2=\text{A}^4\text{B}^6=\text{B}^2$(mod ...
0
votes
1answer
34 views

Redundancy in Performance Measures

I have a performance rating that correlates positively with a variety of other parameters used individually to evaluate the performance rating of a given operation. However, I suspect that many of ...
0
votes
0answers
23 views

How do I choose which design of experiments method to use?

I'm setting up a computer simulation (which I know changes the design of experiments methods) and I can't really determine how to choose which design of experiments (DOE) method to use. I'm a little ...
0
votes
0answers
41 views

Error for combining multiple binomial distributions

This problem is somewhat involved and I have a partial solution so bear with me. I will illustrate the problem with an example. Lets say we have two processes and we want to know which has a higher ...
1
vote
3answers
118 views

How should I analyze my data?

I am new here, so I hope this question is on topic. I understand a little about statistics, but my knowledge of what methods to use in real case scenarios is a little limited. I want to statistically ...
0
votes
2answers
48 views

alternative formulas for standard error of a difference between two means?

I have a question that seems basic but I found two alternative answers online so I thought that I should ask for advice. I have an experiment where each subject makes decisions about target words in ...
0
votes
2answers
50 views

Interactions between covariates

Suppose I have a sample with two covariates whose levels are associated with some response; e.g., the mean height of a plant at 6 months is modeled by two factors: cultivar of plant (say, $A$ versus ...
0
votes
2answers
106 views

Analysis using ANOVA

I want to compare 6 designs of spoons (D1,D2,D3,D4,D5,D6) in 20 children (blocks).I also want to see whether holding the spoon in right or left hand affects food-pinching response(number of M&M's ...
1
vote
1answer
29 views

How is LSD an incomplete three-way layout?

How is the Latin square design(LSD) an incomplete three-way layout? In this context, let me ask also what is a complete layout?
1
vote
0answers
32 views

Is a Chi-squared test sufficient to tell me if my process change was “good enough”?

Experiment Design: Process: Outputs the order in which to do the work (assumption: ordering of work items is most preferred/valuable by stakeholders) Work items: The process above produces a rank ...