1. Random Samples Random digit table
Simple random sample (SRS): every sample of size n has the same chance of being selected

2. Random Samples
probability sample gives each member of the population the same chance of being selected
stratified random sample – Take a random selection from determined homogeneous groups
multistage sample design - multiple samples with increasing precision

3. Random Samples
The fact that every individual has an equal chance of selection, by itself, is not enough to guarantee that the sample is a simple random sample.

4. Random Samples
Sample results do not necessarily match population results.
Results may change from sample to sample, but since we deliberately use chance, the results obey the laws of probability allowing fairly consistent results (within a margin of error).

5. Random Samples
The degree of accuracy can be improved by increasing the size of the sample.