Samplling Flashcards
Sampling Distribution of the Mean
Theorem 1
If all possible samples of size n are drawn with replacement from a finite population of size N, then:
The mean of the sampling distribution of means
µ_x ̅ = µ
The variance of the sampling distribution of means is given by:
〖σ^2〗_x ̅ = σ^2/n . . (iii).
Arising from (iii) σ_x ̅ = σ/√n . . . (iv)
Arising from (iv) the standard score Z = (x ̅- µ)/(σ/√n) . . . (v)
V is a value of the standard normal variate
Theorem 2
If all possible samples of size n are drawn without replacement from a finite population of size N, then:
The mean=
of the sampling distribution of means µ_x ̅ = µ
The variance of the sampling distribution of means is given by:
〖σ^2〗_x ̅ ((N-n)/(N-1)) σ^2/n
Here, σ_x ̅ = √(((N-n)/(N-1)) ) (σ/√n)
How to get no of possible outcomes in sampling
The first was without replacement while the second was with replacement. Without replacement, you are suppose to have NCn means but with replacement you should have N raise to the power n means
Standard error of the sampling distribution of means =
Square root of E (x-mean)^2
—————————————-
Total number of samples