Sampling

Sampling

1. Population

   • Set of things you are interested in

2. Sample

   • Subset of the population

3. Parameter

   • A number that describes the whole population

4. Statistic

   • A number taken from a single sample

5. Simple Random Sampling

   • Every member of population equally likely to be chosen
   • Use random numbers to choose sample

6. Systematic Sampling

   • Find a sample of size n from population size N
   • Take a number from first k numbers and every kth member after that
   • k = N/n

7. Stratified Sampling

   • Split population into distinct groups
   • Sample within each group in proportion to its size

8. Biased if it doesn't represent entire population