sampling

Question 1

population and sample

Answer 1

population - large group of individuals that he researcher is interested in studying often called target population

sample that is drawn ideally needs to be representative of the target population so that generalisation of findings becomes possible

vast majority of samples contain a degree of bias

Question 2

random sample

Answer 2

all members of the target population have an equal chance of being selected

obtain a complete list of all members of the target population

all the names on the list are assigned a number

actual sample is selected through the use of the lottery method such as randomly picking a number

Question 3

strenght of random sampling

Answer 3

unbiased

confounding variables and extraneous variables should be quality divided between the groups enhancing internal validity

Question 4

limitation of random sampling

Answer 4

difficult and time consuming to conduct

complete list of target of target population may be difficult to obtain

may end up with a sample that’s unrepresentative

Question 5

systematic sampling

Answer 5

every nth number of the target population is selected

sampling frame is produced which is a list of people in the target population organised for example in alphabetical order

Question 6

strength of systematic sampling

Answer 6

sampling method is objective

researcher has no influence over who is chosen

Question 7

limitation of systematic sampling

Answer 7

is time consuming and participants may refuse to take part

Question 8

stratified sampling

Answer 8

composition of the sample reflects the proportions of people in certain subgroups (strata) within the target population

researcher first identifies the different strat that make up the population

proportions needed for the sample to be representative are worked out

particpants that make up each stratum are selected using random sampling

Question 9

strenght of stratified sample

Answer 9

produces a representative sample because it is designed to accurately reflect the composition of the population

generlatistipn of findings cecomes possible

Question 10

limitation of stratified sampling

Answer 10

identifies strata cannot reflect all the ways that people are different

complete representation of the target population is not possible

Question 11

opportunity sample

Answer 11

select anyone who happens to be willing and available

simply takes the chance to ask whoever is around at the time of their study

Question 12

strength of opportunity sampling

Answer 12

convenient

less costly in terms of money and time as you don’t need to obtain a target population

no need to divide their population into different strata as there is stratified sampling

Question 13

limitation of opportunity sampling

Answer 13

opportunity samples suffer from two forms of bias

sample is unrepresentative of the target population as it is drawn from a very specific area

findings annoy be generalised to the target population

researcher has complete control over the selection of participants and for instance may avoid people they do not like the look of - researcher bias

Question 14

volunteer sampling

Answer 14

particpants selecting themselves to be part of the sample

Question 15

strenght of volunteer sample

Answer 15

easy to collect

requires minimal input from the researcher

less time consuming than other forms of sampling

ends up with particpants who are more engaged

Question 16

limitation of volunteer sampling

Answer 16

may attract a certain type of person

not representative