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Showing posts from 2010

Stand up to your Defense Panel with Small Non Random Samples

Power and Efficiency at high price Older science (and social science) students remember being told during their one applied statistics course, like “Statistics for Communication” or “Research Statistics” that parametric tests, such as t-tests and analysis of variance are powerful and more efficient in discriminating between true and false hypotheses than non parametric tests. In general, this is true. But the power and efficiency of parametric tests impose a priori stringent conditions: for examples, the level of measurement must be in interval or ratio scales; samples must be randomly selected, and they must be large enough [(or as statisticians love to call them, “asymptotic”); how large can be precisely calculated, provided you have an idea of “tolerable variance”. Some statisticians give 100 approximately, some 50, Walpole allows 30, BUT!!]; they must come from approximately normal populations. How do you know if the population is normal? Well, you must have made certain th

God, Life and Justice: A Personal Decision

There are events in one’s life, the intensity and impact of which bring about the deepest questionings. In mine, such events led me not only to question the meaning of life (which I had always taken to be on the good, or at least tolerable side), but the worthiness of life itself. Being a Catholic Christian, that meant I had questioned whether God was in fact in control over the balance of good and evil, at least in this planet where I lived. These thoughts can go on and on, until they reduce to the paramount issue of whether to continue living decently, or giving in to an ideology akin to Darwinian survival of the fittest, or Hobbes’ war of all against all. I resolved these issues, at least for now (to be honest), by faith (surprise!). I took it on faith that “life is unfolding as it should”, and that I should humbly and patiently wait upon the Lord’s judgment. This wasn’t easy, as we all observe injustice perpetrated repeatedly. But it is true indeed (and by that I mean it c