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The Most Dangerous Equation [pdf]

press.princeton.edu

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Re: The Most Dangerous Equation [pdf]

#3

Post by guylhem »

Absolutely totally true.

Ignore the laws of statistics at your own peril.

Knowledge of statistics is the best investment one can make with one's time. A/B testing is the tip of the iceberg - a simple practical application, which can be exploited much better with statistics.

Learn about statistical distributions - Bernouilli, Binomial, Normal, Poisson and Hypergeometric at least, then Chi distribution to grasp real tests like chi2 goodness of fit, 2 way, calculating intervals - and you will see so many possible daily applications and avoid so many pitfalls (such as the ones outlined in the article)

BTW I saw in another comment something about significance. DeMoivre is not directly related to significance- it only means that if you know the population standard deviation, the standard deviation of any sample extracted from the population will depend on the size of the given sample - ie smaller samples will go below and above the expected value much more often

Consequently, if you try to deduce the SD of a population using a sample, the bigger sampler will give the best results (ie smaller or more accurate intervals)

Re: The Most Dangerous Equation [pdf]

#5

Post by tokenadult »

This book chapter is an interesting read. It illustrates the importance of considering sample size, especially, when looking at preliminary research findings.

After looking up the book from which this chapter is excerpted, I followed other recommendations from Amazon to another very useful book,

http://www.amazon.com/When-Can-You-Trust-Experts/dp/11181302...

When Can You Trust the Experts: How to Tell Good Science from Bad in Education by Daniel T. Willingham, a very astute psychologist with an interest in education policy.

Re: The Most Dangerous Equation [pdf]

#6

Post by jfriedly »

K2h wrote: post #2

so is the conclusion to be that statistically significant sample size is as important as the 'result' when measuring standard deviation? http://en.wikipedia.org/wiki/Sample_size_determination

I don't think so. "Statistically significant" is a relative term and when testing an entire population is infeasible (as it often is), we instead sample some fraction that we believe is "statistically significant" on the assumption that it will accurately reflect the whole.

The point of this article is that a sample only accurately reflects the whole in some ways. Variability in particular scales with the square root of the sample size. And since misconceptions about variability have been at the heart of many controversies (male vs. female intelligence, school size, cancer risk, etc.), De Moivre's equation is important; even dangerous in the sense that ignorance of it has led to billions of dollars wasted.

Re: The Most Dangerous Equation [pdf]

#10

Post by forrestthewoods »

guylhem wrote: post #3

Absolutely totally true. Ignore the laws of statistics at your own peril. Knowledge of statistics is the best investment one can make with one's time. A/B testing is the tip of the iceberg - a simple practical application, which can be exploited much better with statistics. Learn about statistical distributions - Bernouilli, Binomial, Normal, Poisson and Hypergeometric at least, then Chi distribution to grasp real te…

If someone doesn't know much about statistics what is your recommended source to learn from?
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