Sampling Techniques

Sampling Techniques

1. Random Sampling

   • Unbiased
     • Everyone has an EQUAL chance of being chosen
       • Easy and Cheap
   • Lottery Sampling
     • 1) Write member name on card
       • 2) Place cards on hat
         • 3) Draw out required number of tickets
   • Sampling Frame Required
     • Not suitable when population/sample size is large

2. Systematic Sampling

   • Suitable for large population
     • Simple and Quick to use
   • Sampling Frame Required
     • Bias if sampling frame is not random
   • Method:
     • 1) Find Interval: k = total population/sample size
       • 2) Randomly select a number between 1 and k (use random number generator)
         • 3) Select every k^th member afterwards, until sample size is satisfied.

3. Stratified Sampling

   • Accurately Reflects the population structure
     • GUARANTEES Proportional Representation
   • Not suitable if proportion of sample is large
     • Population must be clearly classified into distinct strata
   • Method