Lesson 6- Sampling Methods + Pilot Studies

Question 1

Target population

Answer 1

The group who researchers are studying and want to generalise their results to

Question 2

Sample

Answer 2

Should be representative of the population from which it is drawn and should therefore have the same characteristics as the population
Too expensive to study entire populations so samples are used

Question 3

Random sampling

Answer 3

When every member of the target population has the same chance of getting selected
Put names in hat and draw from them

Question 4

Advantages of random sampling

Answer 4

If target pop is large and a large sample is drawn then it’s likely the sample will be representative, so results can be generalised to target pop

No researcher bias when selecting the sample cause it has been chosen by chance without any conscious choice. Everyone has an equal choice of being selected

Question 5

Disadvantages of random sampling

Answer 5

Sometimes hard to get full details of a target population from which to select a sample. Eg- it is not possible to get a full list of all of the women aged 20-30 as some women might not appear on the list due to being in prison, not being registered etc.

Not all members of the target population who are selected to take part will be available or willing to take part, making the sample unrepresentative. Some people might refuse to take part in a study. This could reduce the sample size too.

Question 6

Systematic sampling

Answer 6

When pps are selective by taking every Nth person from a list
They become your sample

Question 7

Advantages of systematic sampling

Answer 7

Systematic sampling is far more simple than random sampling as it only requires a list of the target population, and then the researcher decides to select every nth person. Random sampling requires a lot more time and effort

Question 8

Disadvantages of systematic sampling

Answer 8

1) The process of selection can interact with a hidden periodic trait within the population. If the sampling technique coincides with the periodicity of the trait, the sampling technique will no longer be representative

Not all members of the target population who are selected to take part will be available or willing to take part, making the sample unrepresentative. Some people might refuse to take part in a study. This could reduce your sample size dramatically too.

Question 9

Stratified sampling

Answer 9

Classifying the population into characteristics and then randomly choosing a sample which consists of pps from each category in the same proportion as the total population
Population divided into strata based on characteristics

Question 10

Advantage of stratified sampling

Answer 10

1) The strength of stratified sampling is that all groups within a population are included, therefore the sample should be representative of the population

Question 11

Disadvantage of stratified sampling

Answer 11

1) Stratified sampling can be very time consuming as the categories have to be identified and calculated. If you do not have details of all the people in your target population or the relevant strata, you would struggle to conduct a stratified sample.

Question 12

Opportunity sampling

Answer 12

Selecting pps who are readily available and willing to take part
Aka convenience sampling

Question 13

Advantage of opportunity sampling

Answer 13

1) This is the easiest and most practical method of ensuring large samples especially when compared to stratified sampling which might be very time consuming and expensive to carry out.

Question 14

Disadvantage of opportunity sampling

Answer 14

1) There is a high chance that the sample will not be representative of the target population. Sometimes people feel obliged to take part in research (especially if someone they know is conducting the research, they might find it hard to say no) even when they do not really want to, this is unethical

Question 15

Volunteer sampling

Answer 15

Involves ppl volunteering to participate in a study

Question 16

Advantage of volunteer sampling

Answer 16

1) This method saves the researcher time and effort. The researcher needs to construct some kind of advertisement for the study and then just needs to wait for the participants to come to them to volunteer their time and involvement. This is better than other sampling methods where the researcher needs to ask people to take part and needs their full commitment.

Question 17

Disadvantage of volunteer sampling

Answer 17

1) A certain type of person tends to volunteer (enthusiastic, interested in your topic) and this means that there is a very high chance that the sample obtained will be unrepresentative and will not accurately reflect the target population (volunteer bias).

Question 18

What is a floor effect

Answer 18

When a task is too hard and participants score very low or cannot complete it at all.

Question 19

What is a ceiling effect

Answer 19

When a task is too easy and participants achieve full or near-full marks

Question 20

What should be checked in a pilot study when using self-report measures?

Answer 20

Whether participants understand the questions and are willing to answer them.

Question 21

Why must closed questions be checked in a pilot study?

Answer 21

To ensure the response options are suitable and cover possible answers.

Question 22

Why might open questions be needed in self-report measures?

Answer 22

To allow participants to give unpredictable or detailed responses.

Question 23

Why is the reporting method checked in a pilot study?

Answer 23

To see if it is appropriate (e.g. changing a face-to-face interview to a questionnaire if it is intimidating).

Question 24

What must observers agree on in an observational pilot study?

Answer 24

Clear operational definitions of behavioural categories.

Question 25

Why might observers need practice during a pilot study?

Answer 25

To improve inter-observer reliability.

Question 26

What should be checked about behavioural categories in observations?

Answer 26

That they include all important behaviours and do not overlap.

Question 27

Why should researchers consider whether observations are covert or overt?

Answer 27

To check whether participants’ behaviour is affected by being observed.

Question 28

Quota sampling

Answer 28

Choosing people that meet the requirements of your study or quota