Date: Jun 8, 2013 7:10 PM
Author: Cristiano
Subject: Re: A "plausible range" for a random variable
On 07/06/2013 19:31, Rich Ulrich wrote:

> Poisson consideration gives a good approximation for small

> proportions. This is applied for your N=2000, 2 1/2%, as follows.

>

> Rank 50 is the point estimate of L. The +/- 2SD range for Poisson

> can be estimated as ( Square(Sqrt(L) - 1), Square(Sqrt(L) + 1) )

>

> The square root of 50 is about 7; the square of 6 is 36, and the

> square of 8 is 64. That gives (approximately) the CI for L=50

> is (37, 65).

When the sample is taken in N(0,1), using your limits for N= 2000 I get

a 73% confidence level. Is that the intended level?

That CI doesn't seem good for other distributions (uniform, exponential,

log-normal and weibull), because I get 0 or 100%. Am I wrong?

Cristiano