Sampling

Question 1

What does population mean

Answer 1

The wider group of individuals the researcher is interested in. From this population they select a smaller sample to study e.g 20-30 participants. Ideally the sample will be representative of the population so that generalisations can be made

Question 2

What are the 5 sampling techniques and the acronym to remember them?

Answer 2

R- RANDOM
O- OPPORTUNITY
S- SYSTEMATIC
S- STRATIFIED
V- VOLUNTEER

Question 3

What is random sampling?

Answer 3

When every member of the target population has an equal chance of being selected

Question 4

What is the process for random sampling?

Answer 4

1. Researcher makes a list of everyone in the population
2. Each person is assigned a number
3. The numbers are then randomly selected e.g. from a hat or a random generator

Question 5

What is opportunity sampling?

Answer 5

Consists of the researcher selecting anyone who is available and willing to take part in the study

Question 6

What is systematic sampling?

Answer 6

Uses a predetermined system to select the participants e.g. every fourth person in a list could be used in the sample, so not everyone has an equal chance of selection

Question 7

What is stratified sampling?

Answer 7

When the researcher ‘stratifies’ the target group into sections, each representing a key group (or characteristic). For example, if a researcher wished to sample different age groups in a school, firstly they would have to identify how many students for each subgroup e.g. ages 10-12 , 13-15 , and 16-18

Question 8

What is volunteer sampling?

Answer 8

When participants self-select to become part of a study because they volunteer or respond to an advert

Question 9

Strengths of random sampling?

Answer 9

• Unbiased
• It is widely accepted that since each member has the same probability of being selected, there is a reasonable chance of achieving a representative sample (generalisation)

Question 10

Weaknesses of random sampling

Answer 10

• Difficult and time-consuming to conduct
• Representative sample is not guaranteed (could all be male by chance)
• Some may refuse to take part

Question 11

Strengths of opportunity sampling

Answer 11

• Easy and inexpensive to carry out
• Often achieves a large sample size through reaching a wide audience

Question 12

Weaknesses of opportunity sampling

Answer 12

• The researcher has complete control over who they select and may avoid people they don’t like the look of (researcher bias)
• Findings can be unrepresentative of the target population e.g. a specific street so findings can’t be generalised

Question 12

Strengths of systematic sampling

Answer 12

• This sample is objective, once the system has been established the researcher has no influence over who is chosen
• This method offers an unbiased chance of gaining a representative sample

Question 13

Weaknesses of systematic sampling

Answer 13

• If the list has been assembled in any other way, bias may be present. every nth person could be of one gender so cannot be generalised

Question 14

Strengths of stratified sampling

Answer 14

• Most representative because it is designed to accurately reflect the composition of the population. This means that generalisation of findings becomes possible

Question 15

Weaknesses of stratified sampling

Answer 15

• It takes more time to plan
• Care must be taken to ensure each key characteristic present in the population is selected across strata, otherwise this will design a biased sample. e.g 1000 students in a school, 300 are 10-12 years old, 500 are 13-15 and 200 are 16-18. Therefore the sub group is 30% , 50% and 20%

Question 16

Strengths of volunteer sampling

Answer 16

• Practical and easy way to gather participants as it requires minimal input from the researcher
• Less time-consuming

Question 17

Weaknesses of volunteer sampling

Answer 17

• Lacks generalisability as those who are willing to give up their time are likely to be different from the target population