Certificate C3 Business Mathematics

What are the methods used to colect a data ?

1. Random : is free from bias and is used to construct a sampling frame

2. Stratified: involves dividing the population into strata or categories. It takes more time but is more representative and sample error should be reduce.

3. Systematic: is a method which works by selecting every nth item after a random start.

4. Multistage: is a probability method which involves dividing the population into number of sub-populations and then selecting a small sample of these sub-populations at random.

5. Cluster: is a non-random method that involves selecting one definable subsection of the population as the sample, that subsection taken to be representative of the population in question.

6. Quota: is forfeited in the interests of cheapness and administrative simplicity. Investigators are told to interview all the people they meet up to a certain quota.