Statistics - Sampling Error
1 - About
Sampling error is due to chance.
2 - Articles Related
3 - Example
- Even the random histogram is not perfectly random, there is some fluctuation due to sampling error.
- From several samples of the same population, you will get a little bit of fluctuation that's just due to chance. That's sampling error
- a mean of 12.03
- a mean of 12.9
- a mean of 14.13
4 - Calculation
Sampling error depends:
- on the size of the sample, relative to the size of the population. As sample size increases, sampling error decreases
- on the variance in the population. As variance increases, sampling error increases
Sampling error is estimated through the Standard error calculation.
5 - Sample Size
The normal distribution when sample size is only 10 (first distribution in the upper left corner), is much much wider than when we have a really large sample (such as 1000 for the last distribution in the lower down corner).
That's because standard error is the standard deviation of this sampling distribution.
As the sample get larger, they're going to squeeze around the mean and the standard error is going to get very low.
This points to the problem of NSHT being bias by sample size.