How to perform a power analysis for a Dif-in-Dif?

How to perform a power analysis to calculate the sample size for a change between two periods between control and treatment group (Dif-in-Dif)?

13 December 2020 4,096 3 View

How optimize the Size Exclusion Chromatography?

Hello! I'll do a size exclusion chromatography, but I only have an open column, and I'll perform the peptide extraction from yeast, using buffer lysis (sodium phosphate 50 mM/NaCl 30 mM/DNAse and...

01 March 2021 2,215 2 View

No title

01 March 2021 3,905 5 View

What test should I use to compare two or three means, if data is not normally distributed but sample size is > 30 in each group?

I personally feel this as a most confusing question. As per my understanding, if sample size is > 30, and sample is skewed, we can still use paramteric approach, as it will follow Z...

01 March 2021 1,587 6 View

Is it necessary to report effect size (ES) in statistics of biomedical research given that we already report p values routinely?

Pls share your thoughts

01 March 2021 7,330 4 View

Why there are two peaks while using the mie plot of Silver nanoparticle?

Hi, I am trying to learn the theoretical modelling of silver nanoparticle using the Mie scattering theory. After that, I discovered a software named Mieplot developed by Philip Laven, where it...

25 February 2021 7,493 6 View

How to calculate Z (the number of molecules in a unit cell) for calculating theoretical density?

I am trying to calculate the theoretical density of my ceramics materials. I use the formula below to calculate the theoretical density: Theoretical density = (Molecular weight x No. of molecules...

24 February 2021 3,823 2 View

How to handle studies which report perfect effect sizes in a meta-analysis using Pearson's r?

I'm in the process of updating a meta-analysis and in one of the new studies, effect sizes are reported as Tau-U. Two of the effect sizes are reported as Tau-U = 1.00. I am using Andy Field's...

24 February 2021 2,265 3 View

Sample size determination for non-parametric tests?

How do I run a a priori sample size determination for non-parametric tests, like the Mann-Whitney U-test and the Kruskall-Wallis or other non-parametric tests that accord with the unpaired t-test...

24 February 2021 166 6 View

How to determine a priori sample size for t-test with unequal means?

I need to conduct a a priori sample size determinations for t-test with unequal means, but I don't know the sizes of the groups nor the ratio of both groups... Can I do a sample size determination...

24 February 2021 8,289 3 View

What are alternatives to factor analysis for a small sample?

My sample size is too small to conduct a factor analysis. I created my own psychometric scale for measuring Effectiveness of Support, which contains 38 items (4 sub-scales) Im really struggling...

23 February 2021 9,287 12 View