Sampling

• What is a sample?

  A group of participants that need to be representative of their target population.
• What is a target population?

  The people that the researcher wants to generalise there findings to.
• Population Validity

  The extent to which the results can be generalised to the target population.
• Opportunity Sampling

  • Readily available people who will take part.

  • Easiest method to use.
• Strengths of Opportunity Sampling

  • Easiest way of obtaining participants SO it is very efficient and least costly.

  • Allows for larger sample to be collected.
• Volunteer / Self-Selected Sampling

  • Place adverts around an area for people to reply to via email or phone number.

  • Researcher will sample out reflected target population.
• Strengths of Volunteer Sampling

  • Allows for a wider range of participants SO allows for representative sample and makes results more generalisable.
• Weaknesses of Opportunity Sampling

  • Sample may not be representative of people around them SO limits generalisability of results to target population.
• Weakness of Volunteer Sampling

  • Biased method as people may only respond if they have strong views on topic SO limits generalisability of results.
• Snowball Sampling

  • Researcher begins with one participant and then asks them to invite another person they KNOW to participant and so fourth.

  • Used if target population is hard to access.
• Strength of Snowball Sampling

  • Easy to obtain SO convenient way to find a certain sample.
• Weakness of Snowball Sampling

  • Non-representative sample as participants are more likely to be similar to each other SO limits generalisability of target population.
• Random Sampling

  • Research will get all names of members apart of the target population.

  • Names are picked out of a hat or name generator until they have enough participants for study.
• Strength of Random Sampling

  •Least biased method as each participant has an equal chance of being picked SO representative and therefore can be generalised.
• Weakness of Random Sampling

  • Difficult to conduct with large target population as you need lots of information SO it is not useful for all types of studies (only use for small samples.)