# Thread: Statistical modeling

1. ## Statistical modeling

If Xis are distributed with mean (mui) and standard deviation (sigma),
and if all the possible samples of size n are drawn from this population

what is
the mean and standard deviation of the sample mean x bar?
the distribution of the sample mean x bar as n increases?
the distribution of the sample mean if x bar is itself normal?

2. ## Sampling Distributions

the mean and standard deviation of the sample mean x bar?
depends on your sample, it may not be very similar to population

the distribution of the sample mean x bar as n increases?
if n is sufficiently large then,
we can assume x bar~N(mean, (sigma^2)/n)

the distribution of the sample mean if x bar is itself normal?[/quote]
N(mean, (sigma^2)/n)
that is because small samples has increased variability

3. Originally Posted by rubic
the mean and standard deviation of the sample mean x bar?
depends on your sample, it may not be very similar to population
yea im still very confused about this isnt it just the formula for mean and standard deviation

but i dont understand what it means to find mean and standard dev of x(bar)
thnx for the other two tey make sense