Sampling

Question 1

What is opportunity sampling?

Answer 1

When the researcher uses people who are available at that time and willing to take part

Question 2

What is a strength of opportunity sampling?

Answer 2

It is quick and easy to conduct as you don’t need to find the whole target population

Question 3

What are 2 weaknesses of opportunity sampling?

Answer 3

• It is unrepresentative as the sample is only from one place so it is hard to generalise to the target population
• There may be researcher bias as the researcher can choose the participants, so may choose desirable ones

Question 4

What is self-selected sampling?

Answer 4

When the researcher uses people who take part in a study who volunteer to participate, they select themselves as participants

Question 5

What are 2 strengths of self-selected sampling?

Answer 5

• Adverts can reach a wide variety of participants e.g. billboards
• It is quick and easy to do as the participants come to you

Question 6

What are 2 weaknesses of self-selected sampling?

Answer 6

• Volunteer bias as they may answer differently trying to be ‘helpful’
• Not a representative sample as only people who see the advert can volunteer

Question 7

What is random sampling?

Answer 7

Every member of the target population has to be available to the researcher. Each person has an equal chance of being picked

Question 8

What are 2 strengths of random sampling?

Answer 8

• Sample is representative as it uses the whole target population in its use
• No researcher bias as the process is completely random so cannot be influenced by anyone

Question 9

What is a weakness of random sampling?

Answer 9

Can be time-consuming as the researcher has to find everyone in the target population, and some people may be hard to find

Question 10

What is systematic sampling?

Answer 10

When participants are selected by being every nth number on a list of the target population

Question 11

What are 2 strengths of systematic sampling?

Answer 11

• Quick and easy as it doesn’t need to generate many random numbers
• Unbiased as it does not require input from the researcher

Question 12

What is a weakness of systematic sampling?

Answer 12

The sample may not be representative as it may miss subgroups by chance

Question 13

What is stratified sampling?

Answer 13

Selecting participants in proportion to their frequency in the target population. Subgroups in the target population are identified and participants are selected at random for the sample in the same proportions

Question 14

What are 2 strengths of stratified sampling?

Answer 14

• Most representative of the target populations as all subgroups are represented so we can generalise the results
• Unbiased as the researcher cannot have an effect on the selecting process

Question 15

What is one weakness of stratified sampling?

Answer 15

Can be time consuming as you have to group the entire target population and then sample it

Question 16

What is quota sampling?

Answer 16

Selecting participants in proportion to their frequency in the target population. Subgroups in the target population are identified and participants are selected by the researcher using opportunity sampling for the sample

Question 17

What is a strength of quota sampling?

Answer 17

It is the most representative of the target population as all subgroups are represented so we can generalise the results

Question 18

What are 2 weaknesses of quota sampling?

Answer 18

• Can be time consuming as you have to group the entire target population and then sample it
• Researcher bias may be present as they use opportunity sampling to get the sample

Question 19

What is the difference between Stratified and Quota sampling?

Answer 19

In stratified sampling, once the characteristics of the target population have been identified, each strata is chosen randomly whereas in quota sampling, it is chosen by opportunity sampling

Question 20

What is snowball sampling?

Answer 20

When current participants recruit further participants from people they know would be suitable for the study

Question 21

What is a strength of snowball sampling?

Answer 21

Enables the researcher to locate groups that may be difficult to access

Question 22

What is a weakness of snowball sampling?

Answer 22

Not representative as it doesn’t use the whole target population

Question 23

EQ - A psychologist is investigating the effect of reading on general intelligence in school children. He puts together an alphabetised list of all the school children in the county, and uses a computerised system to choose 50 students in a random way.
- Identify the sampling method used and give one advantage and one disadvantage of this (4)

Answer 23

• Random sampling
  ADVANTAGE
• Every student in the county has an equal chance to be chosen for the story, so there is no bias from the researcher
  DISADVANTAGE
• May be time consuming to find every student in the county and compile a list in alphabetical order