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  1. victorxstc

    Corona hints

    Hi guys. Thanks for correcting these sentences. Well I thought they were legit, hence the sharing. It was actually good that I shared them, so that you could debunk those myths. About fibrosis though, I searched and saw lung fibrosis is a common side effect of corona.
  2. victorxstc

    Corona hints

    Corona Virus - Info from Stanford Stanford Notes on Coronavirus The new Coronavirus may not show sign of infection for many days. How can you know if you are infected? By the time you have fever and/or cough and go to the hospital, the lung is usually 50% fibrosis. Taiwan experts provide a...
  3. victorxstc

    Precision/Trueness (P90-P10)/2

    You can follow 2 approaches at least: 1. In this method, all you need is a real model, as the gold standard, with known 3D coordinates of reference points marked on it (the more reference points, the better; but of course you cannot have too many reference points). You should carefully measure...
  4. victorxstc

    How's the new look?

    Except me :( no love for victor :p
  5. victorxstc

    How's the new look?

    Wow have you gone mod too? Now I am jealous :)
  6. victorxstc

    How's the new look?

    Thanks a lot quark :) This is awesome. I am still disoriented a little bit but the site is very fluid. I guess the number of thanks has been reset to zero?
  7. victorxstc

    Do TSers pick threads with titles indicating misery or urgent help?

    Following our previous talk, I wanted to compare two TS members right now. I counted how many threads of two TSers had titles like "Please help", "Help", "lost", "Urgent" etc. One of TSers had responded to 25 threads out of about 200 threads they had answered to. The other one had picked almost...
  8. victorxstc

    Binary mixed-model logistic regression using lmer() of lme4 for multilevel analysis

    In my experiment, each patient has been observed twice, once using placebo and the other time using the real treatment. I want to assess the predictive effects of the treatment and patients' demographics (age, sex, etc.). Therefore I have for example 100 patients, but actually 200 pairs of...
  9. victorxstc

    Univariate, Bivariate, Multivariate: Myths and facts

    This is not a question but a summarization of my recent learnings regarding the common mistakes in calling different types of analyses, and to address the proper names for them. I now know that a multiple regression is not a multivariate analysis, although I have seen millions of incorrect...
  10. victorxstc

    Bootstrapped binary logistic regression in R

    I am trying to run a bootstrapped binary logistic regression. I have loaded the dataset manually into Rstudio (don't know the syntax yet! actually the syntax I learned from Rcommander didn't work in Rstudio); and here is my code for the bootstrapped regression (thanks to this site): (the...
  11. victorxstc

    What to do when the predictors are not what I expected (when the model is fine)?

    I would try to clarify the problem and then ask the questions. The problem (variable names are masked due to confidentiality): I ran a binary logistic regression, in which there were 5 independent variables (IVs): A, B, C, D, and E. A and B are my concern. C is also my concern and I would talk...
  12. victorxstc

    Risk Factors in a Clinical Trial

    The study is confidential right now. So I cannot go into the details. But will try to detail every necessary information, in the hope that can get some good advice from you. The design is a clinical trial. We assessed the effect of a material on healing of oral wounds. It turned out to be...
  13. victorxstc

    Contributions to writing code that enable R to analyze the "Descriptive" statistics

    Apparently R does use only the raw data. In some other statistical programs, there is the option to calculate some simple tests, only by inputting the descriptive statistics. I for one think it would be much better if we could enable R to run such tests too. There are not many tests that can...
  14. victorxstc

    Is this study clinical trial or retrospective cohort?

    Hi We have a set of patients with dental implants in their mouths. We wanna evaluate whether implants in each patient's mouth are as sensitive as normal teeth (of the same patient) to tactile stimuli. So it can be a retrospective cohort, because we have split the sample based on the...
  15. victorxstc

    Can a cohort study have no control groups (is a clinical series study a cohort)?

    Hi AFAK a cohort study needs a matched control group. However, its definition doesn't necessitate a control group. Moreover, I have read some publications in which the authors had investigated the complications of some treatments, for example rhinoplasty, during a period of time. They did...
  16. victorxstc

    Is my study case-control or retrospective cohort?

    Hi AFAIK if we split the sample by the exposure, it is retrospective cohort; and if we split it by the disease, it is case control. I am studying the association between malocclusion and the efficacy of mastication. I have divided the sample into two groups: people with and without...