ABSTRACT
As indicated in the previous two topics, simple random sampling gives each member of a population an equal chance of being included in a sample. The resulting sample is, by definition, unbiased, yet it may still contain sampling errors, which are errors created by chance (i.e., created by the random sampling process). The technical term for discussing the magnitude of sampling errors is precision. Results are more precise when researchers reduce sampling errors. The two major ways to reduce sampling errors are to increase sample size, which is discussed in Topics 29 and 30, and to use stratification in conjunction with random sampling, which is called stratified random sampling.
