Lesson 7 (sampling techniques)

Question 1

Population

Answer 1

A group of people who are the focus of the researchers interests
Share a caracteristic (eg, halesowen college students)
Usually too large for each person to be investigated (practical and economic reasons)

Question 2

Sample

Answer 2

A representative and typical sample is taken from the population to investigate the population

Saple findings need to be generalised back to the population
If the sample is unbiased, results can be generalised back to the target population.
Would have population validity

Question 3

Biased sample

Answer 3

Sample that isnt representative of the target population

Question 4

Opportunity sampling

Answer 4

Researcher selects anyone who is readily available and willing.
Simply ask who is available (convenient)

Question 5

Opportunity sampling strength

Answer 5

Convenient
saves time and effort
Less costly

Question 6

Opportunity sampling weakness

Answer 6

Unrepresentative of the target population, drawn from specific area
Researcher bias: Researcher has control over the selection of participants

Question 7

Volunteer sampling

Answer 7

Participants select themself to be part of the study (self selection)

Researcher places an advertisement asking for volunteers

Question 8

Volunteer sampling strength

Answer 8

Easy, requires minimal effort, less time consuming
Ends up with participants who are engaged

Question 9

volunteer sampling weakness

Answer 9

volunteer bias: may attract a certain profile/type of person, one who is curious and more likely to try and please the researcher (generalisability)

Question 10

Random sampling

Answer 10

All members of the target population have an equal chance.
Complete list of all members, they are assigned a number, sample selected through the lottery method.

Question 11

Random sampling strengths

Answer 11

Reduces chance of biased sample: extraneous variables shpuld be equally divided between groups

free from researcher bias: researcher has no control over who is selected

Question 12

Random sampling weakness

Answer 12

Time consuming: complete list of target population is diffucult to obtain

Representative sample is not guaranteed - chance that sub groups are overrepresented or non selected

Question 13

Snowball sampling

Answer 13

Participants from a rare group.
Researcher identifies one participant then asks them to suggest other participants
Typically utilised on hidden populations such as drug dealers, criminals or sex workers

Question 14

Snowball sampling strengths

Answer 14

Enables researchers to conduct studies when finding participants might be otherwise challenging

As participants are used to locate other participants, it takes less time and money

Question 15

Snowball sampling weakenss

Answer 15

Bias is certain as participants are selecting members. Someone who is well known and sociable is more likely to take part than an introvert

Researchers have little control over the sample. They will have little knowledge of wether the sample is representative

Question 16

Systematic sampling

Answer 16

Every nth number of a target population is selected
A sampling frame is produced: eg. list of people in target organised into alphabetical order
A sampling system is nominated (every 3rd, 6th or 9th person ect)
May begin from random start to reduce bias

Question 17

Systematic sampling strength

Answer 17

If the list order has been randomised, offers a unbiased chance of gaining a representative sample

Question 18

Systematic sampling weakness

Answer 18

Time consuming, participants may refuse to take part, more of a volunteer sample

Not entirely unbiased unless the number selected for sampling is chosen randomly

Question 19

Stratified sampling

Answer 19

Has the same % of a specific characteristic as the target population

Represents people in certain subgroups

Participants that make up each subgroup are selected using random sampling

Question 20

Stratified sampling strength

Answer 20

Produces a representative sample as it accurately represents the composition of the population, generalisable.

Avoids researcher bias. selected randomly

Question 21

Stratified sampling weakness

Answer 21

Not perfect. cannot reflect all the ways that people are different

Question 22

Quota sampling

Answer 22

a sub group is identified, and is represented as a percentage of the whole population

Then selected with opportunity sampling

Question 23

Quota sampling strength

Answer 23

More representative than opportunity sampling, equal representation of sub groups

Question 24

Quota sampling weakness

Answer 24

Can be time consuming.

Weaknesses of opportunity sampling