Hendrik Bruns

19 Questions 43 Answers 0 Followers

Questions related from Hendrik Bruns

How to test whether a moderation is mediated?

I would like to test for mediated moderation as in the attached path diagram. I obsered that the effect of binary treatment (X) on behavioral outcome (Y) depends largely on the moderator (Mod). I...

05 May 2019 3,852 3 View

Is mediation analysis adequate to answer whether subjects that respond to X strongly are also those that perceive it in a certain way?

Consider an experiment where an intervention X was manipulated and the behavioral outcome Y observed. After observing the outcome, a post-experimental questionnaire asked respondents about their...

05 May 2019 4,785 2 View

How to test for causal mediation with instrument for mediator?

I've got a question regarding the intersection of mediation and instrumental variables. I want to test if a randomized treatment variable (T) has a direct effect on outcome (Y), as well as an...

05 May 2018 9,875 6 View

Does it make sense to vary prior information as a sort of sensitivity analysis?

Is it a valid approach, when estimating a bayesian model, to build a 3-dimensional graph which plots the bayesian model estimates of the coefficient (y-axis) dependent on different assumed prior...

01 January 2018 7,376 4 View

Compare means with Mann-Whitney Test?

A Mann-Whitney-Test is often used as an alternative to the t-test when data is not normally distributed. However, both test different hypothesis. While the t-test compares means of the groups, the...

12 December 2017 4,733 9 View

How to connect theory, causal reasoning and experimental design?

The goal of an experiment is to test why something happens, i.e. testing the cause of an effect. I can understand this via two different ways: 1) Intervention T causes Behavior B (B happens...

08 August 2017 1,166 5 View

What if less observations feasible than suggested by a priori power analysis

For an experiment, a priori power analysis suggests that I need N observations in order to detect an effect E with a power of 80%, alpha = 0.05. What are my options if I run the experiment but,...

07 July 2017 6,082 9 View

Experiment to choose prior for follow-up experiment?

Imagine I conduct an experiment where I compare outcomes in a Treatment (T) to a Control (C). The study is under-powered, judged by observed power (which I was asked to calculate due to lack of an...

06 June 2017 198 8 View

Type I error control dependent on experimental design?

If I want to test two hypothesis, i.e. whether Treatment 1 (T1) affects outcome O, and whether Treatment (T2) affects outcome O, relative to a control group (C), does it make a difference with...

06 June 2017 9,251 4 View

Regressing change score conditionally censored on pre-test outcome

I conducted an experiment where subjects made two decisions. the first (Pre) decision was unaffected by any treatment, whereas subjects made their second decision (Post) after being randomly...

05 May 2017 8,352 3 View

Latent or observed variable in structural equation models?

I am new to structural equation modeling. I am wondering whether the decision to include a variable as a latent or observed variable is solely theoretical. For example, I have experimental data...

03 March 2017 5,373 5 View

Is it ok to use MWU to test between-group differences on change scores?

I have two measurements of a variable per observation, one pre- and one post-treatment. Although my IV (Treatment) has more than 2 levels, my question does also apply to te case with only 2...

01 January 2017 9,684 3 View

Difference between regression on change scores and regression on post-treatment measurements controlling for pre-treatment measurements?

My DV is measured two times per observations, once pre- and once post-treatment (interval scale). The IV has multiple levels and is categorical. I am interested in how the different levels of the...

01 January 2017 7,370 9 View

Is there a difference between ANOVA analysis of change scores and repeated-measures ANOVA?

I measure a continuous variable prior and after treatment allocation in a 3x4 factorial experimental design . The pre-treatment measurements are all unaffected by the treatment. There is no...

11 November 2016 7,009 5 View

Can confidence intervals substitute for power analysis?

After reading papers on power analysis (e.g. Colegrave & Ruxton 2003 in Behavioral Ecology; Goodman & Berlin 1994 in Annals of Internal Medicine) I got the following impressions: a)...

11 November 2016 7,288 6 View

Block and stratified randomization possible?

I aim to allocate subjects to four different experimental groups by means of Permuted Block Randomization, in order to get equal group sizes. This, according to Suresh (2011, J Hum Reprod Sci) can...

11 November 2016 8,035 4 View

Is it ok to complement observations of an experiment with additional observations after analysis of data to enhance robustness?

Assume having conducted an experiment. You find a marginally significant interaction effect (10% significance) but, regretting not having performed a pre-experimental power analysis, you judge the...

09 September 2016 7,909 4 View

When and how to block on/ create covariates when testing interactions in experiments?

Assume you want to test an interaction between a treatment and a subject-specific covariate. The covariate, i.e. its score is constructed from answers to items of a questionnaire. Each answer to...

09 September 2016 3,547 4 View

Are significant differences strengthened by relatively small sample sizes?

In the footnote of a paper published in the Journal of Economic Behavior & Organization in 2007, the authors Kuang et al. write the following two sentences: "Given the idiosyncrasy of random...

08 August 2016 5,750 8 View