Sampling

Question 1

What are the 5 types of sampling?

Answer 1

1. Random
2. Opportunity
3. Volunteer
4. Systematic
5. Stratified

Question 2

What is random sampling, how is it done and what are its strengths/ weaknesses?

Answer 2

• A form of sampling where all members of the target population have equal chance of being selected

1. Obtain a list of all members of target population
2. All names on the list are assigned a number
3. Sample is selected by a random number selector

Strength: The sample will be unbiased and is the most representative as everyone has an equal chance of being selected

Weakness: It’s difficult and time consuming as a complete list of target population may be difficult to obtain

Question 3

What is opportunity sampling and what is its strengths/ weaknesses?

Answer 3

• The researcher takes the chance to ask whoever is around at the time of their study

Strength: Easier and more convenient as it doesn’t cost as much and is also quicker as a list of members from a target population isn’t required and there is no need to divide the public

Weakness: Unlikely to be representative as it has 2 forms of bias-
1. It’s drawn from a specific area, so findings cannot be generalised to a target population
2. The researcher has control over the selection of participants, so they may avoid people they don’t like the look of

Question 4

What is volunteer sampling and what are its strengths/ weaknesses?

Answer 4

• Involves participants selecting themselves to be part of the sample (seeing an advert in a newspaper and volunteering)

Strength: It’s easy and convenient as it’s less time consuming and participants are more engaged as they volunteered themselves

Weakness: Unlikely to be representative as it’s bias because asking for volunteers may attract a certain profile of person

Question 5

What is systematic sampling and what are its strengths/ weaknesses?

Answer 5

• When every ‘nth’ number of a target population is selected and a sampling frame is produced (such as a list of target audience organised into alphabetical order)

Strength: The researcher has no influence in who is chosen, reducing any biases

Weakness: It’s time consuming and participants may refuse to take part

Question 6

How is stratified sampling done and what are its strengths/ weaknesses?

Answer 6

1. Researcher identifies the different strata that make up the population
2. Proportions needed for the sample to be representative are worked out
3. Participants who make up each stratum are selected by random sampling

Strength: Likely to be the most representative, as it’s designed to accurately reflect the composition of the population, meaning generalisation of findings becomes possible

Weakness: The identified strata cannot reflect all the ways that people are different, so complete representation of the target population isn’t possible