Sampling Distributions — Summary
Copyright © 2008–2012 by Stan Brown, Oak Road Systems
| Data type | Numeric Data | Binomial Data |
|---|---|---|
| Statistic of one sample | mean x̄ = ∑x/n | proportion p̂ = x/n |
| Parameter (unknown) of population | mean μ | proportion p |
| Sampling distribution of the ... | mean | proportion |
| Mean of sampling distribution | μx̄ = μ | μp̂ = p |
| Standard deviation of sampling distribution | SEM = standard error of the mean | SEP = standard error of the proportion |
| σx̄ = σ/√n | σp̂ = σ/√n = 
(Use p̂ if p is unknown.) |
|
| Shape: sampling distribution is normal if ... | original distribution is normal or n ≥ about 30 | np(1−p) ≥ about 10 and 20n ≤ population |
| NOTE: n is number of individuals per sample. Number of samples is indefinitely large and has no symbol. | ||