sampling

Question 1

define population

Answer 1

a (large) group of people who are the focus of the researchers interest, from which a small group/ sample is drawn,

Question 2

define sample

Answer 2

a group of people who take part in an investigation. The sample is drawn from then target population and is presumed to be representative of the population.

Question 3

what is a random sample?

Answer 3

a sophisticated form of sampling in which all members of the target population have an equal chance of being selected.

Question 4

Evaluate random sampling

Answer 4

It is potentially unbiased. CVs and EV’s should be equally divided between different groups, enhancing internal validity.
However it is time consuming and difficult (the last may be hard to obtain)You may end up with a sample that is unrepresentative. Selected pp’s may refuse to take part

Question 5

How would you carry out a random sample?

Answer 5

1. obtain a complete lost of all members of the target population.
2. assign all names a number.
3. select the sample through a lottery method (randomiser etc)

Question 6

what is a systematic sample?

Answer 6

where every Nth member of the target population is selected (every 3rd house or 5th person etc)

Question 7

evaluate systematic sampling

Answer 7

this method is objective. The researcher has no influence on who is chosen once the system has been established. Therefore it isn’t biased
However it is time consuming and some pp’s may refuse to take part.

Question 8

How would you carry out a systematic sample?

Answer 8

1. a sampling frame is produced (list of people in target pop) and organised into an order (eg alphabetically).
2. A sampling system is nominated (eg 8th person) or may begin randomly to reduce bias.
3. Researcher then works through the list to produce a sample.

Question 9

what is an opportunity sample?

Answer 9

when a researcher decides to select anyone who happens to be willing and available . They ask anyone who is around at the time of their study (eg in the street where it will take place)

Question 10

evaluate opportunity sampling

Answer 10

It is convenient for the researcher. Less time consuming and inexpensive as the researcher won’t require a list and doesn’t have to divide the pop.
However the sample is unrepresentative of the target population as it’s drawn from one area so findings can’t be generalised. Also, researcher has control over the selection so may avoid certain people.

Question 11

what is a stratified sample?

Answer 11

a sophisticated form of sampling in which the sample reflects the proportions of people in certain subgroups (strata) within the pop.

Question 12

how would you carry out a stratified sample?

Answer 12

1. Identify the different strata that make up the population.
2. work out the proportions that are representative of them.
3. the pp’s that make up each stratum are selected randomly
   EXAMPLE: if 40% of people in Manchesters population were city fans, in a sample of 20, there would be 8 city fans.

Question 13

evaluate stratified sampling

Answer 13

produces representative samples so generalisation is possible.
However, the identified strata can’t reflect all the ways people are different so complete representation isn’t possible.

Question 14

what is a volunteer sample?

Answer 14

involves pp’s selecting themselves to be part of the sample (self selection)

Question 15

how would you carry out a volunteer sample?

Answer 15

researcher may place an advert in a newspaper or or a notice board etc
or willing pp’s may raise their hand when the researcher asks

Question 16

evaluate volunteer sampling

Answer 16

collecting a sample is easy, it is less time consuming as it requires minimal input from the researcher (pp’s come to you). Researcher ends up with pp’s that are more engaged and won’t refuse instead of someone who was randomly stopped in the street.
However, asking for pp’s may attract a certain “profile” of a person, like someone who is curious and more likely to try and please the researcher. Findings may be hard to generalise.