Recent content by Roundtoit

  1. R

    linear regression and repeated measures ANOVA

    I am trying to determine the best way to analyze some repeated measures. The scores are numerical activity scores ( such as 0.005678, 0.0075689 etc) recorded every few seconds over a period of 4 hours in the interventional arm of my study. So only analyzing within participant and within group...
  2. R

    sample size for dichotomous outcome in retrospective observational study

    I really need some help here seeing if I can get this right. I seem to come up with something different every time. I am testing the hypothesis that there is no difference in the timing of removing chest tubes to the development of significant pleural effusions after surgery requiring drainage...
  3. R

    sample size calculation, planned multivariate regression

    The primary outcome is seen in the literature as about 6-10% incidence. I am looking at time of an intervention as it relates to outcome development. What makes it more complex is that I am also looking at multiple other variables to see if there will be association with the outcome as I...
  4. R

    Logistic regression for prediction of outcome?

    yes essentially. pleural effusion requiring drainage after surgery. The argument currently is that drainage tubes are removed too early which leads to effusion formation, solution: leave tubes in longer. my hypothesis is, that is nonsense, earlier drain removal makes no difference. All these...
  5. R

    Logistic regression for prediction of outcome?

    specifically trying to determine correlational factors that might lead to the outcome of pleural effusion requiring drainage after surgery. So for example, do those with surgery times over 100mins have more likelihood, or do those that have a fluid balance over a certain value in the ICU have...
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    Logistic regression for prediction of outcome?

    I am designing a project and am inexperienced with the statistical analysis to say the least. I am trying to determine the predictive factors associated with the risk of developing an outcome. Its a complex project as their are multiple variables with the potential to impact the incidence of the...
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    standard deviation greater than variance, is this ok?

    I am putting together some audit results and it was suggested I present them as mean +/- SD. However there is a significant variance in the results. For example looking at hours it took to achieve a targeted temperature goal : results varied from 0 hours to 11. Using excel I ended up though with...
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    interpretation of a negative risk difference

    Hi, I am reviewing a cohort study and trying to make sense of the results. When considering mortality they presented their results as a risk difference which is a little different to what I normally see. Usually reported is RR or OR. In this case the results give a negative number. -35% (95%CI...
  9. R

    propensity matching and ITT for cohort study

    I am reviewing a cohort study that used a retrospective database to determine if treatment with hypothermia post cardiac arrest improves survival to discharge. They used what seems like fairly robust propensity matching analysis. However they then adjusted afterwards again with sensitivity...