What is the sample size in cross-sectional studies?

I am doing a cross-sectional study, I want to find the sample size. the study is on the prevalence of neuropathic pain in knee osteoarthritis. I will use raosoft.com margin of error 5% and CI 95%

20 February 2019 3,899 2 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

Can the problems of overfitting be solved without cross validation?

For an overfit data set the cross validation error will be much bigger than the training error. Is it true or false?

23 February 2021 3,616 2 View