SRS

Simple Random Sampling. Sampling without replacement of every possible sample with equal probability.

Taking a random sample from a population with every sample having the same probability of being chosen. Use RNG.

Probability of a sample being chosen = N!/n!(N-n)!

Total Estimate = mean*N

Variation of sample mean = S^2(1-f)/n f = n/N = sampling fraction
 * Std error = sqrt(S^2(1-f)/n)

S^2 = population mean variance = 1/(N-1)*sum(yi-y(mean))^2

Finite population correction =