Questions tagged [experiment-design]

The study of how to structure an information-gathering exercise where variation is present.

Filter by
Sorted by
Tagged with
0
votes
0answers
9 views

Does there exist an accepted term for the opposite of a holdout?

A holdout is a group of users who are prevented from entering any experiments conducted on a website and kept as a kind of “global” control group. The purpose of a holdout group is to compare the ...
1
vote
0answers
21 views

Causal inference method for analyzing randomized control trial with covariates / pre intervention observations

I've got a seemingly easy situation, which turns out to be a little more complex than originally thought. Here's the Setup: We have a randomized controlled trial. Test and Control groups are the same ...
0
votes
0answers
5 views

Choosing a statistical test for three trials with continuous outcome

I have some data that represents three trials where cell populations were divided into two evenly sized groups. One group received no treatment while the other group received treatments (the ...
1
vote
0answers
5 views

How to calculate number of participants and stimuli for experiment to reach significance?

I am running an experiment to determine the best performing of 5 systems, labeled A-E. I plan on running pairwise comparisons, e.g. is A better than B, A vs C, etc.? For the sake of argument, we can ...
1
vote
0answers
19 views

How would a study in which a clinical group and a healthy control group both receive the same intervention be classified?

I need to classify the design of a study in which 2 groups receive the same intervention and are compared regarding specific outcome parameters (pre-post difference). One group consists of subjects ...
0
votes
1answer
52 views

Regression when both input and dependent variables are percentages

I have a dataset where I am trying to understand if there is a correlation between two variables: an input which is the percentage of a group that is white (which varies between 40% and 95%), and an ...
0
votes
0answers
13 views

Points of mass in running variable in RD design

I am trying to run a fuzzy RD design using Stata, where the running variable is municipal population. However, when I try to compute the optimal bandwidth using ...
2
votes
1answer
23 views

experimental design - repeated measures within factor combinations?

Sorry for what might be an obvious question, but I have a question about an experimental design for which I can create a "mouse" analogue: I have 270 mice. I have 2 treatments (factors)-- L ...
2
votes
0answers
9 views

De-aliasing two-factor interactions in a Plackett-Burman design

what I've got so far is a 2-level experiment design with 10 factors and 32 experiments, which is made of a resolution III Plackett-Burman design that I folded (complete foldover) so that it is a ...
0
votes
0answers
8 views

How to handle strong ceiling effects in an repeated measurment experiment?

i am trying to analyse some old data. It's an between-within subject experiment with 4 experimental conditions and 2 points of measurment. The question is, if there are differences in effect of the ...
0
votes
0answers
19 views

Designing a stats experiment on Life Time Value (LTV) of the customers of a subscription product

I work for a subscription product that has two different channels in which customers can subscribe. Let's call them channel A (website) and channel B (mobile application). I have a hypothesis that ...
1
vote
1answer
93 views

regression to the mean and its formula in R

In this book, the estimate of the regression to the mean phenomenon is said to be: $Prm=100(1-r)$. Where $Prm$ is the percent of regression to the mean, and $r$ is the correlation between the two ...
0
votes
1answer
24 views

what could be the possible nuisance variables for this experiment?

I'm new to statistic and I'm considering the experiment of calculation ability between people who customarily paying in cash and paying in cashless. Hypothesis here is "People who customarily ...
3
votes
1answer
34 views

How to extend Plackett-Burman design to further explore the interactions?

My situation is as follows: I have built a 2-level Plackett-Burman design with 10 factors (some are actual 0/1-variables, the others are numeric and I used the minimum and the maximum) and 32 ...
1
vote
1answer
21 views

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 ...
1
vote
0answers
19 views

Are these the major response variable types?

I am a biologist with an interest in experiment design. I recently refreshed my memory about what kinds of response variables that are possible, and made this chart (see jpeg). I would like feedback ...
1
vote
1answer
27 views

Between-subject design and within-subject anlyses

I have a between-subject design in which there are two groups (A, B) and two conditions (x, y). I ran an ANOVA and found no interaction whatsoever and no significant differences in the two conditions. ...
0
votes
0answers
8 views

How to apply statistics tool on my microcosm experiment?

I don't have a strong command of statistics. I did an experiment regarding the growth of microbes in a microcosm (Salinity and Temperature). How can I correlate the population data with salinity and ...
0
votes
0answers
19 views

Factors given by DoE can experimentally not be reached

We are running a DoE in a CCD manner at the moment. One factor is quite difficult to reach and to reproduce: Humidity because it has to be set by chemical reactions. To be more concise: The factor 56 %...
1
vote
1answer
28 views

How many unit are necessary in randomized experiment?

Let's say we want to conduct an experiment with binary treatment. How do I decide how many units do I need to assing the treatment to, to get internally valid results? I understand that you need to ...
0
votes
0answers
8 views

Choice-based conjoint (CBC) - randomized design

I need some advice re/ randomized designs in CBC: In my CBC, I have n = 220 and 10 pair-wise comparisons, i.e., each respondent evaluates 20 choice options in 10 choice tasks. Each choice options has ...
1
vote
0answers
67 views

Nested Experimental Design: Intuition about power?

I am planning a nested experimental design, where 1000 participants respond to one policy proposal coming from a 2^3 design (125 participants for each condition A x B x C). Yet, the policy proposal ...
1
vote
2answers
105 views

Is it valid to write a hypothesis using the result of THIS experiment to predict an original independent variable?

There is a dataset/study that has two independent binary variables, and a continuous dependent variable. ...
1
vote
1answer
37 views

Winsorizing propensity scores

Is it kosher? Inverse propensity weights (IPW) has been shown to perform poorly when selection probabilities are small (Kang and Schafer, 2007). Are there any standard solutions to this issue?
1
vote
1answer
18 views

Compute Standard Deviation for the Mean of Means

I need some help with the statistical analysis of an experiment. It would be great if you could cite on what literature you base your answer if possible. For simplicity let us assume I have 3 ...
1
vote
0answers
14 views

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 ...
4
votes
1answer
34 views

Is my design nested or crossed? Question concerning specifying random effects with lmer in R

I've run an experiment where 120 participants (PP) viewed 40 quotes (Item) each (presented in Facebook format) and were asked to ...
2
votes
1answer
40 views

Is this correct use of linear mixed model?

This is the current data I have I want to know if fixed factor A has any effect on C. That is, if A1 = A2 = ... = A5. I think I am trying to find a group difference, correct me if I am wrong. ...
3
votes
0answers
51 views

Extending external validation diagnostics to experiments with continuous treatment

Does the external validation diagnostic methods discussed in Stuart et al. (2011) (i.e., inverse propensity score weighted regressions) also apply to the experimental setting in which the treatment is ...
1
vote
1answer
23 views

Basic question about measurement errors in Design of Experiments

After reading and applying many examples of DoE I have a question that has been bugging me and haven't found an answer so far. Usually what we see in an example or publication is the design table with ...
0
votes
0answers
15 views

How can I write the response surface methodology (RSM) equation from coefficients including block effect?

I fitted a model by rsm function in R, and here is the code: rsm1 = rsm(x ~Block+FO(x1,x2,x3)+PQ(x1,x2,x3), data=t1.df) The coefficients, obtained from the rsm1$...
0
votes
1answer
23 views

My Design defines the Hypothesis test?

a conceptual question appear in my mind and i need help, in pratical therms, whats defines the statistical test its my hypothesis and my experimental design ? Using this example, if i am interrested ...
2
votes
2answers
70 views

Using Latin Hypercube Sampling with a condition that the sum of two variables should be less than one

I am building an experimental design with 4 variables defined on (0,1). In notation, $x_i \in [0,1]$ with $ i=1,..., 4$). Two of these variables must satisfy the condition that $x_1 + x_2 \leq 1$. ...
0
votes
0answers
19 views

What is the best statistical analysis to use for the below example (psychology research)

I am currently choosing the best statistical design for my Psychology MSc research. I am looking into the effects of BMI (underweight, normal, overweight), SES (Low, high) and Ethnicity (Categorical) ...
1
vote
0answers
23 views

Repeated measures design: Must each participant receive ALL 4 versions of a given stimulus? [closed]

I am creating a 2x2 repeated measures design where a given stimulus object has four possible versions (2 factors with 2 levels each create 4 unique object versions). In the ideal repeated measures ...
1
vote
0answers
22 views

Codebook/survey design and modeling: How to deal with a large share of intentionally missing values? [closed]

In my final data set I have a high proportion of missing data (1/4 are NAs, 35/52 variables have NAs), because of my codebook design: I only coded features (how things were discussed) that occurred in ...
2
votes
0answers
21 views

Pre-posttest x Fixed Effects Design

I am planning a 2x2x2 design which includes 1 within factor and 2 between factors. However, the within factor is a pre-test post-test design, meaning that the order of the two treatments of the within ...
0
votes
0answers
11 views

What to do if some conditions of DoE are hard or impossible to run?

Assume we have 3 factors with 2 levels each. If I understood it correctly, for small number of factors we can consider a full factorial design, in this case would be 2^3 full factorial design. What ...
2
votes
1answer
38 views

Do I have to randomize all drug trials?

This thought experiment I came up with has been bugging me. Let's say I want to test the effectiveness of Drug A vs Drug B on reading speed (no placebo necessary). I KNOW for a fact that the effects ...
0
votes
1answer
27 views

Conditional treatment effects for RCTs

I have randomized controlled trial data with one control and two treatments. Since the DV is continuous, I estimate the treatment effect using an lm model, while ...
0
votes
0answers
22 views

Why confounding factor has to correlated with independent variable?

One assumption of linear regression is the independent variables should be independent of each other. But in experimental design, when we build a linear regression to measure the causal impact of the ...
4
votes
1answer
31 views

What statistical tests should be performed to test effect of trials on response times where each subject has different number of data-points?

I am running a behavioral experiment where a number of subjects (=20 in my case) perform a simple cognitive task. The experiment consists of a fixed number of trials (say, 40 in my case). During each ...
1
vote
2answers
30 views

Can a “crossed” experimental design compare a continuous and categorical variable?

Would it be incorrect to refer to an experimental design as "crossed" if one of the treatments is a continuous variable rather than a categorical variable? The continuous variable covers roughly the ...
1
vote
1answer
40 views

How is it decided to use Difference in Differences, Regression Discontinuity or both together (if possible) according to the policy change?

I am quite new at (quasi) natural experiment analysis, so please bear with me, and got some questions. In my research, I am planning to use one policy change which happened 2002 and treated firms are ...
0
votes
2answers
27 views

Apply normality assumption on limited sample size

I now have a measurement which only gives me: i) the range of values (continuous in nature), say, 110.0 to 160.0 without the access to the actual underlying data from which these statistics are ...
0
votes
0answers
17 views

What kind of test for percentages of different groups?

I've set up a little experiment using 5 different treatments (including the control group) for control of crown rot in harvested bananas. For each treatment, I took around 18-20 banana clusters and ...
2
votes
1answer
42 views

What to do if the range of an input factor changes after running the experiment?

I am gaining my first experiences in Designing Experiments and here where I am stack: An experiment has been run with some continuous input factors: x1, x2, ..., x5. The goal of the experiment was to ...
3
votes
2answers
60 views

Optimal unbalanced design for A/B test

I want to find the right way to distribute variants (control/test) in A/B-test with the constraint of no more 10 percent of population in test group. The test is t-test for continuous metric. I can ...
1
vote
1answer
26 views

Sample Size Calculation considering Gradual Improvements to Treatment Group

I have an experiment with two equally sized groups. These groups contain machines and the metric being measured is the failure rate of the of the groups. In a typical experiment setting, the test ...
1
vote
1answer
27 views

Which additional experiments would best improve the model?

I have been given some data on a biotechnological process stemming from a multitude of different (kind of independent) experiments. The process has a lot of potentially relevant inputs (temperature, ...

1
2 3 4 5
29