The population is chosen by a set interval and random numbers are usually used to decide on the intervals
The population is often chosen by geographical convenience a cluster sample is used randomly chosen clusters of the population
Allocate each person or item a number from 001 to the total number of items or people in the sample. Move along the random number table in the number of digits your highest number in the sample. Ignore 00, repeats and numbers greater than your sample
The population is divided into strata then the samples from each strata is chosen by convenience
Divide each of the population into strata. Random samples are then taken from each strata in proportion to the size of each strata
