sampling

• sample - group of people taken from a wider population that will be studied
• sampling frame - a list of all the people forming a population where a sample is taken
• research population - a wider population of people that is of interest to the researcher.
• random sampling - every participant has an equal chance of being selected for the sample.

  • strengths - unbiased
  • weakness - large sample makes it time consuming
• systematic random sampling - all data is sequentially numbered and every nth piece of data is chosen. n = size of population/desired sample size.

  • strength - easy to select in wider population
  • weakness - hard to produce a representative sample if small
• stratified random sampling - involves dividing the sample frame into a number of sections (strata)

  • strengths - it is representative
  • weakness - can be difficult and time consuming to collect the relevant strata groups.
• snowball sampling - done by interviewing one person and asking for reccomendation on suitable people to interview.

  • strengths - good way to access hard to reach groups
  • weakness - not representative as you only gain access to specific people that may not reflect the characteristics of your wider population.
• volunteer sampling - when participants choose to take part in a study on their own.

  • strengths - easy to recruit and low cost
  • weakness - has a high bias and limited generalisability due to the low representativeness
• opportunity sampling - when a group of people are available to take part in the study

  • strengths - quick and easy
  • weakness - not representative
• purposive sampling - when researchers choose a particular group or place to study because it's known to be the type that is wanted.

  • strengths - data collected is valid.
  • weakness - causes bias and unrepresentative
• quota sampling - researcher fills a quota/target based on specific characteristics, until the quota is met, such as race, gender, age.

  • strengths - cost effective and allows for easy comparison of sub groups
  • weakness - not representative and can be subject to researcher bias