samle size

  1. A

    Chi square on a huge dataset

    I have a situation where I want to look if a simulation gives expected values, so I think a chi squared is the way to do this. Some of the expected probabilities are quite tiny, but others are very large. After doing a chi square I noticed it gives a huge value = 867551.351! I see online that...
  2. S

    Sample size calculation

    Dear All, I am a vascular surgeon planning a research project. I need some advice regarding the sample size calculation. I am looking at the same group of patients pre and post-procedure looking for a change in the diameter of their main blood vessel at 2 different points. We have some data...
  3. L

    Sample Size problem: Have done a trial/pilot, but how to proceed?

    I have a problem in calculating sample size. I did do a small pilot experiment, so this is some sample data with the same structure: df <- data.frame(ID = c(1,2,3,4,5,6,7,8,9), School = c("A","A","A","B","B","B","C","C","C"), Test_Method_A =...
  4. F

    small sample size

    Hi everyone! Nice to meet people do same things on the web:) Here the question: I have independent two group of patients first group have 10 patients second have 5 patients can I compare their surgical corrections (advancement measured as milimeters) with ManWhitney test? (since the...