sample estimate

  1. R

    Sampling Twitter Accounts

    Hello, I need to do a content analysis of certain types of Twitter accounts. There are in total 19 of them (N = 19) but I need to take a sample due to resource constraints. I want to have 95% confidence (Z = 1.96) and a margin of error of 5% (E = 0.05). In order to understand the variability of...
  2. P

    Sample size calculation

    Hi everyone! Can anyone helps with calculation sample size for trial? We are planned 2/3 phase with group-sequential design (two stage) with re-estimation procedure for some rare disease (to prove superiority), expected succes rate in treatment group is around 85%, and 75% for control group...
  3. H

    How to estimate population statistics for each category ?

    I have data from a simple random sample having n elements which I’m using to estimate my overall population statistics (mean). My population can be divided into k categories, and I know the composition of my overall population in terms of these categories. As part of my study, I want to estimate...
  4. S

    Sample size calculation

    I need to study the outcome of an intervention in a disease. I will be doing a prospective observational (longitudinal) study in a single cohort (I am not sure if i'm correct - I mean, I will be taking only a single group of diseased undergoing the proposed intervention). The prevalence of the...
  5. S

    Sample size calculation for prospective observational study studying outcome of an intervention?

    Hello everyone, I am submitting proposal for thesis and I need help with the sample size calculation. My study is: to study the outcome of "x" intervention in "y" disease The prevalence of disease is 2.6%. How do I calculate the needed sample size? What else information do I need from the...
  6. I

    Sample Estimate expression in Brunner-Muenzel test with R (lawstat)

    Dear Talk Stats Community, I try to provide a reasonable interpretation of Sample Estimate expression P(X<Y) + .5*P(X=Y), which is shown as an output for BM-test in R (lawstat package). I am confused with the relationship between the following three probabilities: P(X<Y), P(X>Y), P(X=Y)...