Sampling

Sampling

1. Simple random...

   • + No bias (AO3)
   • - Some people may not be in the target market (AO3)
   • Individuals are randomly selected from a population and everyone has an equal chance of selection (AO1)
     • - See what the population think as a whole (AO4)
     • - Important : Accurate results
     • + Random # generator (AO2)
     • + Raffle at a fair (AO2)

2. Quota...

   • Splitting the population into sub-groups according to the distribution of the population (AO1)
     • - Important: More money for research (AO4)
     • - Depends how many people the ask (AO4)
     • + OLAY asking Women about their face cream (AO2)
   • - Interviewer could be bias as to who he chooses (AO3)
   • + Cheaper (AO3)

3. Systematic...

   • When every 'nth' element from a list is selected from a randomly selected starting point (AO1)
     • - How many people need to be asked (AO4)
     • - Important: More money for research (AO4)
     • + Asking for student opinions of a register (AO2)
   • - May be bias if the list is in a specific order (AO3)
   • + Cost effective (AO3)

4. Convenience...

   • + Cheap and easy (AO3)
   • - Bias depending on your location (AO3)
   • Sample of people who you see on that day, influenced by time and location (AO1)
     • - If the business has the time to do it (AO4)
     • - Relies on when/where its taken (AO4)
     • + Standing in a clothes shop asking people favorite burger (AO2)

5. Stratified...

   • + Cost effective/based on proportion (AO3)
     • - Some people may not be in the target market (AO3)
   • Represents each group by sampling each group in proportion to the size of the group (AO1)
     • - Important: ensures valid results (AO4)
     • - Depends whether the sample sizes are correct (AO4)
     • + Asking people from Science, Art and Maths in the correct proportions (AO2)