Sampling

Question 1

define population

Answer 1

A group of people who are the focus of the researcher’s interest, from which a smaller sample is drawn.

Question 2

Define sample

Answer 2

A group of people who take part in a research investigation. The sample is drawn from a (target) population and is presumed to be representitive of that population.

i.e. it stands ‘fairly’ for the population being studied

Question 3

define sampling technique

Answer 3

The method used to select people from the population.

Question 4

How many types of sampling are there

Answer 4

5

Question 5

What are the 5 types of sampling

Answer 5

• random
• systematic
• stratified
• oppertunity
• volunteer

Question 6

what is random sampling

Answer 6

A random sample is a sample of participants produced by using a random technique such that every member of the target population being tested has an equal chance of being selected.

Question 7

Describe the process of random sampling

Answer 7

1. complete a list of all the members in the target population.
2. put all the names in a hat
3. pull out the desired number of names

Alternative method is that names are assigned a number and the sample is generated through the lottery method - a computer based randomiser or numbers from a hat.

Question 8

What is systematic sampling

Answer 8

systematic sampling is a method of obtaining a representative sample by selecting every nth person.
This can be random is the first person is selected using a random method; then you select every 5th, 7th, 10th person after this.

Question 9

Describe the process of systematic sampling

Answer 9

1. a sampling frame is produced, which is a list of people in the terget population organised into, for instance alphabetical order.
2. A sampling system is nominated (every 3rd, 6th or 8th person etc.) or this interval may be determined randomly to reduce bias.
3. The researcher then works through the sampling frame until the sample is complete.

Question 10

what is stratified sampling

Answer 10

Stratified sampling is a sampling technique in which groups of participants are selected in proportion to their frequency in the population in order to obtain a representitve sample.
The aim is to identify sections of the population, or strata, that need to be represented in the study. Individuals from those strata are then selected for the study using random technique.
If the sample is not randomly selected from the stratum, it is then a quota sample.

Question 11

define opportunity sampling

Answer 11

Opportunity sampling is a sample of participants produced by selecting people who are most easily available at the time of the study

often used for market research - have people in off the street

Question 12

define volunteer sampling

Answer 12

a sample of participants produced by a sampling technique that relies solely on inviting people to take part.

Question 13

define bias

in the context of sampling

Answer 13

in the context of sampling, when certain groups may be over or under-represented within the sample selected.
For instance, there may be too many younger people or too many people of one ethnic origin in a sample.

Question 14

What is the result of bias in sampling

Answer 14

It limits the extent to which generalisations can be made to the target population.

Question 15

Eval - strengths - Random sampling

Answer 15

• Free from researcher bias - the researcher has no influence over who is selected and this prevents them from choosing people who they think may support their hypothesis.

Question 16

Eval - weaknesses - random sampling

Answer 16

• difficult and time-consuming to conduct. A complete list of the target population may be extremely difficult to obtain.
• May still end up with an unrepresentitive sample, less likely that oppertunity sampling but still possible that 20 people selected are psychology teachers called joyce. Due to the laws of probibility.
• Participants may refuse to take part - end up with more of a volunteer sample.

Question 17

Eval - strengths - systematic sampling

Answer 17

• avoids researcher bias - once the system for selection is established the researcher has no influence over who is chosen.
• Usually fairly representative, it is possible but unlikely to get an all-male sample.

Question 18

Eval - weaknesses - systematic sampling

Answer 18

• difficult and time-consuming to conduct - a complete list of the target population may be extremely difficult to obtain.
• Selected participants may refuse to take part - end up with a more volunteer sample.

Question 19

Eval - strengths - stratified sampling

Answer 19

• avoids researcher bias - once the target population has been divided into strata, the participants that make up the numbers are randomly selected and beyond the influence of the researcher.
• produces a representitive sample - designed to accuratly reflect the composition of the population - good to generalise.

Question 20

Eval - weaknesses - stratified sampling

Answer 20

• stratification is not perfect - the identified strata cannot reflect all the ways that people are different, so complete representation of the target population is not possible.
• difficult and time-consuming to conduct - a complete list of the target population may be extremely difficult to obtain.
• Selected participants may refuse to take part - end up with a more volunteer sample.

Question 21

Eval - strengths - opportunity sampling

Answer 21

• convinient - saves the researcher time and effort especially compared to random sampling.

Question 22

Eval - weaknesses - opportunity sampling

Answer 22

• sample is unrepresentitive of the target population - drawn from one very specific area i.e. one street in one town. - findings cannot be generalised
• suffers from researcher bias - researchers have complete control ove selection of participants.
• participants may choose not to participate so end up with more of a volunteer sample.

Question 23

Eval - strengths - volunteer sampling

Answer 23

• easy to obtain a sample - minimal effort from the researcher - less time consuming.

Question 24

Eval - weaknesses - volunteer sampling

Answer 24

• volunteer bias - asking for volunteers may attract a ‘profile’ of a person, one who is helpful, keen and curious - impacts generalisability