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  1. GretaGarbo

    Including Five-Number Summaries on a Side-By-Side Boxplots Graph

    What are the five numbers? And where do you want them in the graph?
  2. GretaGarbo

    [SPSS - Mixed Models] Repeated measurements data from randomised controlled trial

    I would not be surprised if walking distance is a skewed distribution so that taking the square root or taking logs would cure som of that (or change from normal distribution to a skewed distribution, like maybe the gamma distribution?). Also taking visits as 0, 1 and 8 seems that you have an...
  3. GretaGarbo

    t-test or any other form of statistical analysis?

    It seems like the values are increasing for the days and also changing for concentration. So it seems like a two way analysis of variance can be used (estimating the two main effects concentration and days, but not the interaction effect). A regression model (which is almost the same thing as...
  4. GretaGarbo

    Which Statistical test is it?

    The OP just need to learn what these test are about. Then it will be more clear about which is the relevant.
  5. GretaGarbo

    Which Statistical test is it?

    How do you do each one of them?
  6. GretaGarbo

    Which Statistical test is it?

    Look in a textbook about what is an " Independent samples t-test" and "Independent samples z-test". Then, what does that mean?
  7. GretaGarbo

    Which Statistical test is it?

    What do they mean by: " Independent samples t-test" and "Independent samples z-test"? When do the use these test?
  8. GretaGarbo

    Can we do discriminant analysis if the data is on Likert scale

    Yes, why not? It seems OK for me.
  9. GretaGarbo

    Skewed Population distribution.

    Well, if your population of interest are the N=45 person in your office corridor and you want to know something about the mean of them, and you have interviewed 15 of them, then you have talked to 1/3 of the population, so you know a lot about the whole population. So the standard error will...
  10. GretaGarbo

    Skewed Population distribution.

    I just believe that the estimate of the skewness works in the same way as an estimated mean from an finite population. There the usual formula for the variance in the mean is: s^2/n But when you are sampling from people, a finite population, you can add a finite population term, so that the...
  11. GretaGarbo

    Skewed Population distribution.

    Yes, bootstapping is a good idea. The size of the population is irrelevant.
  12. GretaGarbo

    Skewed Population distribution.

    Sorry I can't see any question about a superpopulation, so I don't understand that. In my view the population size does not matter. The usual model is that you draw a sample from an infinite normal population. You can weight your self an infinite number of times for example. The OP believed...
  13. GretaGarbo

    what is the command to automatically winsorize a continuous variable?

    What do you mean by "winsorise" ("winsorise a continuous variable")?
  14. GretaGarbo

    When to give up on a regression model

    If it is time to failure it seems more natural to go to Weibull and Cox regression. Look at the Kaplan Meier estimator also. But please note that the R^2 is not a quality index of your work. It is not very important by the way. Some parts of nature are noisy. That how it is. Some are not so...
  15. GretaGarbo

    Reporting Log Transformed T-Test Results

    Yes, the mean in the normal distribution will be an estimate of the expected value. But it will also be an estimate of the median in the normal distribution, since the population mean and the population median is the same. But what is the median in the normal distribution, the mu, will also...
  16. GretaGarbo

    How serious are violations of regression assumptions

    As we have said before, if you want to forget the assumptions then you can also forget to infer something from the data. You input data in the computer and the computer will show you numbers. That is all you can conclude. So, instead of forgetting about the assumptions, forget about that program.
  17. GretaGarbo

    Immortality & Bayesian Statistics

    Jabba said: So P(E|H) is 1 and P(E|~H) is 1. Jabba also said (in #132): "I propose that P(D|~H) is virtually zero, P(~H) is .99, P( E|~H) is about .60 and P(H) is .01." Where E and D is the same. These things does not go together. You must make up your mind. Then just plug it in in Bayes...
  18. GretaGarbo

    Immortality & Bayesian Statistics

    What is E? Isn't E the evidence? The evidence that you are alive. (Not even Decartes had doubts about that.) Isn't it so that the the probability of being alive is one for both hypothesis? So that P(E| H) =1 and P(E| ~H) =1? You are absolutely sure that you are alive, are you not? Then what...
  19. GretaGarbo

    Extracting p-values from an glmmML fitted model

    Maybe the the lmerTest package can give you another "happy". "lmerTest Package: Tests in Linear Mixed Effects ModelsAbstract:One of the frequent questions by users of the mixed model function lmer of the lme4 package has been: How can I get p values for the F and t tests for objects returned by...
  20. GretaGarbo

    Immortality & Bayesian Statistics

    Not that I have any answers to Jabbas statements. But for curiosity: What is the "hypothesis" H? What is the data? What is the distribution for the prior? and what is P(H)? and where have you got that probability from? What is the distribution used for the likelihood?