Comments on: Example of the law of small numbers http://www.johndcook.com/blog/2008/01/25/example-of-the-law-of-small-numbers/ The blog of John D. Cook Sat, 31 Jul 2010 07:45:27 -0400 http://wordpress.org/?v=2.8.4 hourly 1 By: Manoel Neto http://www.johndcook.com/blog/2008/01/25/example-of-the-law-of-small-numbers/comment-page-1/#comment-1192 Manoel Neto Fri, 06 Jun 2008 03:32:41 +0000 http://www.johndcook.com/blog/2008/01/25/example-of-the-law-of-small-numbers/#comment-1192 Ah, I get it. Why I didn't think that before? Maybe because my statistic teacher didn't stressed the probabilities part of the course. Or, either, because I was worried about doing the calculations right to go well in the test, but didn't make the connections between things like this. Anyway, Thanks! Ah, I get it. Why I didn’t think that before? Maybe because my statistic teacher didn’t stressed the probabilities part of the course. Or, either, because I was worried about doing the calculations right to go well in the test, but didn’t make the connections between things like this.

Anyway,
Thanks!

]]> By: John http://www.johndcook.com/blog/2008/01/25/example-of-the-law-of-small-numbers/comment-page-1/#comment-1123 John Wed, 04 Jun 2008 13:47:31 +0000 http://www.johndcook.com/blog/2008/01/25/example-of-the-law-of-small-numbers/#comment-1123 Manoel, Thanks for your note. Here's where the 41% comes from. First think about the probability of four responses followed by one failure: 0.8<sup>4</sup> * 0.2. But this is only one possibility. The failure could be the first patient, or the second, etc. for a total of five possibilities. So we need to multiply the preliminary probability by 5. The result is this 5 * 0.8<sup>4</sup> * 0.2 = 0.4096, which I rounded up to 0.41. Manoel,

Thanks for your note. Here’s where the 41% comes from. First think about the probability of four responses followed by one failure: 0.84 * 0.2. But this is only one possibility. The failure could be the first patient, or the second, etc. for a total of five possibilities. So we need to multiply the preliminary probability by 5. The result is this 5 * 0.84 * 0.2 = 0.4096, which I rounded up to 0.41.

]]> By: Manoel Neto http://www.johndcook.com/blog/2008/01/25/example-of-the-law-of-small-numbers/comment-page-1/#comment-1117 Manoel Neto Wed, 04 Jun 2008 13:21:39 +0000 http://www.johndcook.com/blog/2008/01/25/example-of-the-law-of-small-numbers/#comment-1117 Dear, I liked a lot of the post. However, would You mind to show us the calculations you did to get this result of 41%? Thanks in advance and Congratulaions for the Blog. You are in my RSS, even though I am a political science graduate student in Brazil. Dear,

I liked a lot of the post. However, would You mind to show us the calculations you did to get this result of 41%?
Thanks in advance
and Congratulaions for the Blog. You are in my RSS, even though I am a political science graduate student in Brazil.

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