Comments on: Statistical humbug

By: Michael R. Eades, MD

Michael R. Eades, MD — Tue, 28 Feb 2006 03:24:30 +0000

I’m not crazy about Omegasentails because they are made from flax seeds, which means that the primary omega-3 fat is alpha-linolenic acid (ALA). According to the ads for the stuff there is some DHA added, but I don’t know how much and I don’t know what the quality is.

Humans don’t use ALA well; they must first convert it to EPA then to DHA. I’ve always figured that if that’s what it needs to get to and your trying to supplement, why not just go with the EPA and the DHA and not worry about the conversion.

Good quality fish oil is EPA and DHA with no ALA in the mix.

By: Diana Fairbanks

Diana Fairbanks — Sat, 18 Feb 2006 16:05:16 +0000

Are you familiar with a product called “omegasentails” based on the research of German doctor Johanna Budwig? I found this product at http://www.mnwelldir.org/docs/nutrition/coc_recipes.htm#Omegasentials1
Just wondering if you would recommend it….

By: Michael R. Eades, M.D.

Michael R. Eades, M.D. — Sat, 21 Jan 2006 02:35:21 +0000

Precisely.

By: Mike Dodge

Mike Dodge — Fri, 20 Jan 2006 20:27:08 +0000

Good old statistics. I’ve spent most of my life as a quality or reliability engineer so I know a lot about statistics. Your analysis was good, but I would expand it a little.

As you showed, the ’1.43 (0.33-6.25)’ means that their was no statistical difference between the two groups. But what if the results were ’1.43 (1.01-6.25′? In this case there is a statistically meaningful difference between the two groups. But is the difference really 43% as would be reported? No, the difference is statistically 1%. Whey? Because, at the 95% confidence level that the limits were established at, the lower limit is the one the defines the only limit that is meaningful. Sure the 43% was the mean difference between the two groups, but it is not at the 95% confidence limit. If the 43% is to have a statistical significane, then the results would have to be something like 1.43 (1.42-1.45).

Unfortunately the mean difference is always reported and used as if it were a meaningful number. A 43% difference sounds a lot better than a 1% difference.