Market Research-Sampling issues

While most companies will not be able to afford to conduct a census they will be able to use a sample to conduct their market research.  A sample should bea cross-section of the population.  There are a number of stages that need to be followed prior to a sample:

Stage 1 Define the population of interest
Stage 2 Choose the data collection method
Stage 3 Choose the sampling frame
Stage 4 Select a sampling method
Stage 5 Determine the sample size
Stage 6 Develop operational procedure for selecting sample
             elements
Stage 7 Execute the sampling plan

Sampling errors
There are a number of sampling and non-sampling errors.  Sampling errors result when the sample selected is not perfectly representative of the population.  This can be an administrative error, or a naturally occuring  random error.

There are four probability sampling methods:

1. Simple random sampling
2. Systematic sampling
3. Stratified sampling
4. Cluster sampling

Non-probability sampling

1. Convenience sampling
2. Judgement sampling
3. Quota sampling
4. Snowball sampling