Linear Mixed Model

The more I read statistics, the more I don’t know!

During my time as a medical student (in early 90′s, t-test & chi-square are already the most sophisticated statistical tests on earth. People don’t even bother to run One-way ANOVA to compare variances of 3 or more means. Then I learn about regression. My MPH thesis was using survival analysis. Yup, those with cox-regression. That time I already know about GLM (General Linear Model), which is a group of procedures that utilise t-test, ANOVA, regression and the like) where observations are independent and fixed. What if the dependent variable still continuous but the there are correlation between independent variables? That’s when Linear Mixed Model (LMM) come into the picture.

The most important thing to know is the hierarchical model. What is hierarchical effect? If you understand linear regression, it will be easy for you to understand hierarchical modelling or multi-level analysis. Linear regression analyses effects at one single level. What is level?

To be continue….

One Comment

  1. Gapakulus September 22, 2008 at 5:16 pm #

    The biostats that you’ve lamented really blow my mind off. No wonder one statistician consult is soh expensive. During my undergrad days, I’ve not even heard of ANOVA (that’s in the very late 90′s. Now, I’ve to use it for my master thesis stat analysis. The practice of straight away using non-parametric tests seems acceptable nowadays, as my prof commented about it, and my power of study is only 0.8, heheh, or even lower. What-to-do, aiya, what the heck la.

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