# Homework Help: Re:Statistics: Applications of sampling thoery

1. Mar 21, 2004

### SparkimusPrime

Edit:

Moved from statistics -

I'm doing some homework over the break (!) so I don't have access to my usual lines of help. I've hit a wall:

I don't really know how to solve a problem like this, from the replies to the previous thread I know I have no idea of the concepts being discussed here.

Also:

I get the mean correctly, but the standard deviation does not come out correctly, it integrates to sqrt(2) / 12. Its supposed to be a normal distribution, with mean of 0 and standard deviation of 1, but damned if I know how to integrate the standard deviation correctly:

(this is correct, the notation is standard for the TI-89)

mu = mean = integral( w * sqrt(18) * (w-(2/3)),w,0,1 ) = 0

var = integral(w^2 * sqrt(18) * (w-(2/3)),w,0,1) - mu^2 = sqrt(2) / 12

(this is incorrect, the root of the answer [the standard deviation] is clearly not 1. I think I may in fact be mixing up my equations.)

Peter