1. K

    Sum of questionnaire score - ordinal vs interval? and choosing an inference test

    Hello there, I'm doing a module in research methods and we are required to analyse some data (provided to us) from a randomised control trial. I'm having some difficulty deciding on what stats analysis to do... Background: the primary outcome measure is the sum of scores from a 36 item...
  2. M

    RCT: estimation of total sample size knowing only the percentage of occurrence

    Dear all, I was asked to estimate the minimum sample size to set up a RCT comparing a standard dose technique to detect recurrence of disease vs low-dose technique. It seemed to be reasonably to me to think about differences in sensitivity and to suggest a noninferiority trial comparing the...
  3. E

    How to handle missing data?

    Hi, I just finished an online study in which participants filled out several questionnaires at baseline and after 6 weeks (posttest). There were two groups a control group and an intervention group. The intervention group received online treatment and control group was a waiting list...
  4. N

    Assistance Requested in Determining the Appropriate Statistical Analysis

    I am developing a mock research proposal. The study will be a RCT of 100 women from a health clinic. Both groups complete an initial questionnaire as well as a follow up questionnaire (same as the baseline minus the socio-demographic portion). Both are asked to set up an appointment for a cancer...
  5. G

    comparing change from baseline (two treatment groups, binomial data)

    I am comparing the effectiveness of a vaccine in reducing the prevalence of the targeted protein. I have baseline data (before the vaccine was even available), and now have data from vaccinated and non-vaccinated individuals. I have used chi-square/odds-ratios to show that the prevalence of...
  6. S

    How can i calculate the sample size in this situation?

    I am designing a RCT between two interventions (two closure techniques of abdomen after an operation) to assess their safety, the safe intervention will have the less percentage of outcome (dehiscence). The problem is that i know the outcome of one intervention (p1): 0.2 % while for the other...
  7. B

    Need help with power analysis!

    Hi all, I need some help with conducting a power analysis for a 3 arm equivalence trial, with 2 treatment groups and 1 control group. Is there anyone who could let me know how this could be done? or guide me to relevant readings? Any input is much appreciated. Thanks Bumblebeeeee!