# Thread: Sampling Distributions Help

1. ## Sampling Distributions Help

Suppose that a random sample is to be taken from a normal distribution for which the value of the mean Theta is unknown and the standard deviation is 2. How large a random sample must be taken in order that
E[ |Xbar - theta|^2] <= 0.1 for ever possible value of theta?

2. $\displaystyle E[|\bar X - \theta|^2]$ is the variance of X bar

and the variance of the sample mean is $\displaystyle {\sigma^2\over n}$

So set $\displaystyle {4\over n}\le .1$

3. ## Sampling Distributions Help - Again

I was just curious as to how this problem would be solved if the question were changed to :

E[ |Xbar - theta|]<= 0.1

Thanks