L6 - Sampling Techniques & Pilot Studies Flashcards

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1
Q

Target population

A
  • group researchers are studying and want to generalise results to
    E.g. all females aged 20-30 who shop online
  • sampling techniques are used to obtain sample of target population - can avoid studying whole population as would take too long and be too expensive
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2
Q

Sample

A

Should be representative of population from which it’s drawn and should have the same characteristics as population
E.g. reflect social classes/ethnicities etc…

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3
Q

Random sampling

A
  • every member of target population has same chance of being selected
  • place population names in had then select sample
    e.g. first 20 names chosen out of 100
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4
Q

Advantages of random sampling

A
  • if target population is large and large sample is chosen then it’s likely sample will be representing so results can be generalised from sample to target population
  • no researcher bias when selecting sample, as it’s been chosen by chance without any conscious choice from researcher - equal chance of being chosen
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5
Q

Disadvantages of random sampling

A
  • can be difficult to get full details of a target population from which to select a sample
    E.g. getting women aged 20-30 may be hard as some not registered/in prison
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6
Q

Systematic sampling

A
  • Participants selected by taking every Nth person from a list
    E.g. make list of total population then choose every 6th person to be part of sample
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7
Q

Systematic sampling advantages

A
  • simpler then random sampling as it only needs a list of target population then the researcher chooses every nth person - random sampling needs more time/effort (writing names on slips etc..)
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8
Q

Systematic sampling disadvantages

A
  • selection process can interact with hidden periodic trait within population, if selection coincides with periodicity of trait then it would no longer be random
  • not all members of target population who are selected will be available/willing to take part - could make sample unrepresentative, some may refuse to take part, reduces size dramatically
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9
Q

Stratified sampling

A
  • classifying population into categories and then randomly choosing sample consisting of participants from each category in same proportions as in population
  • population divided into strata in terms of characteristics e.g. age, gender etc…
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10
Q

Stratified sampling advantages

A
  • all groups in population included so it should be representative of population
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11
Q

Stratified sampling disadvantages

A
  • Can be very time consuming as categories have to be identified/calculated, if you don’t have details of all people in target population/relevent strata it would be harder to conduct sample
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12
Q

Opportunity sampling

A
  • select participants who are readily available and willing to take part
  • known as convenience sampling - select participants as it’s convient to do so
  • may have easy access to a group of people they know well/have regular contact with
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13
Q

Opportunity sampling advantages

A
  • Easiest and most practical method
  • especially compared to stratified sampling which may be expensive and time consuming
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14
Q

Opportunity sampling disadvantages

A
  • High chance it won’t be representative of target population
  • sometimes people feel obligated to take part in research (esp. if they know person) even if they don’t want to - this is unethical
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15
Q

Volunteer sampling

A
  • people volunteer to participate in study - researcher usually advertises for people to take part through leaflets, posters, radio or TV broadcasts
  • means people take notice of info and then can decide if they would like to take part in research and volunteer time
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16
Q

Volunteer sampling advantages

A
  • saves researcher time and effort
  • just need to construct some type of advertisement and then wait out for the participants to come to them and volunteer time and involvement
  • better then other methods where researcher needs to ask people to take part and ask for full commitment
17
Q

Volunteer sampling disadvantages

A
  • a certain type of person tends to volunteer (enthusiastic, interested about topic) and this means there’s a high chance that sample obtained will be unrepresentative and won’t accurately represent target population - (volunteer bias)
18
Q

Pilot study

A
  • A pilot study is an initial run-through of the procedures to be used in an investigation; it involves selecting a few people and trying out the study on them.
  • It is possible to save time, and in some cases, money, by identifying any flaws in the procedures designed by the researcher.
  • can help the researcher spot any ambiguities (i.e. unusual things) or confusion in the info given to participants or problems with the task devised.
  • Sometimes the task is too hard, and the researcher may get a floor effect, because none of the participants can score at all or can complete the task - all performances are low.
  • The opposite effect is a ceiling effect, when the task is so easy that all achieve virtually full marks or top performances and are “hitting the ceiling”.
19
Q

Pilot study - self-report

A
  • When using self-report measures it is important to check as part of the pilot study:
    • The participants understand the questions and are prepared to answer them
    • That closed questions offer suitable options
    • Whether open questions are also needed to elicit unpredictable responses
    • Whether the reporting method is appropriate, e.g. if a face-to-face interview is too intimidating should it be changed to a questionnaire?
20
Q

Pilot study - observations

A

In observations it is important to check:
• Observers agree on operational definitions of behavioral categories
• Inter-observer reliability - do the researchers need practice observing the behaviours?
• The behavioural categories include all the important behaviours
• The behavioural categories do not overlap
• Whether the participants are affected by the observers - should they be covert?

21
Q

Pilot study disadvantage

A
  • can be misleading due to small sample size, may not show problem that would be visible in a large sample size
22
Q

Pilot study advantage

A
  • it can identify problems in the study beforehand, saving time and money