Advanced Statistical Analysis

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Questions related to Advanced Statistical Analysis

How to develop and validate questionnaire?

I am in the middle of questionnaire development and validation processes. I would like to get expert opinion on these processes whether the steps are adequately and correctly done. 1. Items...

06 June 2019 2,126 16 View

How to convert a hazard ratio for 3 different categories to a single hazard ratio for 2 different categories?

I am doing a meta-analysis of the validity of immunotherapy as a prognostic factor. Different studies report different categories for drug timing, making them difficult to combine. For example, if...

06 June 2019 4,540 1 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...

27 May 2019 1,526 2 View

In a case control study design, suppose you wish to do correlation analysis between two continuous variables, can both the groups be clubbed as one?

Suppose I am doing a Case control study. Lets say Group 1 is a clinical population (N=30), Group 2 is a healthy control population (N=30). I have measured various variables (Continuous data) in...

14 May 2019 3,601 10 View

Mediation Analysis: Total effect is not significant but Direct effect is significant?

The a, b, and c' paths are significant but the c path is not. What does this mean? I did bootstrapping and the indirect effect is within the confidence intervals and the intervals did not include...

05 May 2019 2,237 4 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 4,803 2 View

Mediation Effects Between Groups?

I have a mediation model and have tested the effects of the model. My mediation variable does significantly and fully mediate the IV and DV. My question is can I test for significance between the...

29 April 2019 9,797 0 View

Appropriate statistical test for my data?

I need to analyse some data in IBM SPSS statistics 21. I'm a novice to statistical testing and hope someone could enlighten me. Research is looking into the relationship between breed size and...

23 April 2019 5,051 6 View

Which interrater-reliability should I use for my study (ordinal data)?

Hello! I made a small post mortem computed tomography study on 5 corpses with 5 different scan protocols to evaluate the "best" protocol (=best image quality) for a native cardiac examination....

17 April 2019 8,483 1 View

Higher order of interactions increases P value as well as R^2. how to interpret them?

4 factors each with 3 levels Full factorial DOE is already been done. To generate a prediction model, linear regression analysis is to be done. i have two cases. 1. no interaction between the...

10 April 2019 1,925 10 View

Does anyone know how to implement restricted permutations for multivariate analysis of split split plot experiments in R?

I wish to analyze the effect of tillage, nitrogen and cover crops on weed communities. The design can be described as the following: - 4 blocks - main plot factor: tillage (nested in blocks) -...

04 April 2019 6,030 1 View

What is a good statistical approach to determine whether there are specific vulnerable time periods during childhood in regards to childhood abuse?

We have collected retrospective data on different forms of childhood abuse adult patients, as well as current physical and mental impairment. The questionnaire on childhood abuse included a...

04 April 2019 8,266 6 View

In Hayes' process Model 1, what does it mean if the conditional effect of moderator is partially effective?

Hi, I am doing my research using Hayes' model 1, simple moderation. I got result that the moderating effect is significant, however, I don't get the meaning of this one below: Conditional...

04 April 2019 6,118 1 View

What factors are important in the design of response surfaces?

It is required to know the important factors to consider, when designing response surfaces. Examples of response surface designs with levels of fertilization in wheat. Software for this type of...

04 April 2019 3,611 2 View

How to find the percentage difference between two groups from a Mann Whitney U Test?

Hi, I am conducting a Mann Whitney U test to compare CTX (biomarker) scores in athletes vs control groups. Although I have found no signifcant difference, I am still looking to make a statement...

04 April 2019 8,650 6 View

How to obtain an Optimized equation based on the data?

I'm trying to obtain an optimized equation such as A as a function of (B,C,D,E), but I'm not knowing where to start with and how to use Matlab to obtain the coefficients for B,C,D,E. The below...

04 April 2019 6,299 3 View

When Cronbach Alpha should not be used as a method to test consistency?

Hi, Several studies have used Cronbach Alpha to test the consistency between the groups of Likert Scale surveys. I have doubts that some of these studies have made a mistake by using this method...

04 April 2019 3,941 3 View

Does anyone know how to implement restricted permutations for multivariate analysis of split split plot experiments in R?

I wish to analyze the effect of tillage, nitrogen and cover crops on weed communities. The design can be described as the following: - 4 blocks - main plot factor: tillage (nested in blocks) -...

03 April 2019 4,413 1 View

How to calculate probability of bacterial colonies found within a specified area?

We are aiming to isolate bacteria using membrane filtration. I would like to test for the probability of bacterial colonies growing towards the center of 47mm diameter membrane vs growing at the...

29 March 2019 9,931 2 View

EFA (exploratory factor analysis), CFA (confirmatory factor analysis) or both?

Greetings, apologies if my question crosses over with others already asked. I am designing a questionnaire with the aim of determining the existence of relationships between latent variables. I...

19 March 2019 6,314 11 View

How to calculate probability of bacterial colonies found within a specified area?

We are aiming to isolate bacteria using membrane filtration. I would like to test for the probability of bacterial colonies growing towards the center of 47mm diameter membrane vs growing at the...

03 March 2019 9,080 3 View

Hello everyone, Could you please help me find the best way to analyze my data?

Hello everyone, Could you please help me find the best way to analyze the following: my outcome is the rate of cognitive decline measured by the difference between two iqcode scores ( iqcode at...

03 March 2019 4,018 5 View

Can you use a t-test instead of an ANOVA in a multi-factorial design if you're interested in only one comparison?

Hi, I have a question about statistical analysis, specifically ANOVA and the paired sample t-test. I’m currently preparing an experiment, in which I will measure RTs in a task that involves...

26 February 2019 9,362 4 View

How to kill a marine sponge underwater instantaneously?

I'm working with time sensitive samples and I need to find a way to kill sponge pieces underwater instantaneously. I cannot wait to to do it on the boat. Someone suggested dropping the piece into...

17 February 2019 5,344 3 View

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