sampling

Question 1

define population

Answer 1

group of people from whom the sample is drawn

Question 2

explain opportunity sampling

Answer 2

ppts happen to be available at the time so are recruited convieniently

Question 3

give strengths of opportunity sampling

Answer 3

• easy method of recruitment –> time saving and cheaper

Question 3

give limitations of opportunity sampling

Answer 3

• not representative of whole population hence lacks generalisability
• researcher bias as they pick ppts

Question 4

explain random sampling

Answer 4

all members of the population have the same equal chances of being selected
- each member in a population is assigned a number then a random number generator is used

Question 5

give strengths of random sampling

Answer 5

• no researcher bias

Question 6

give limitations of random sampling

Answer 6

• time consuming, need a list of everyone + contacting time
• volunteer bias as ppts can refuse so can lead to unrepresentative sample

Question 7

explain systematic sampling

Answer 7

predetermined system is used where every nth member is selected from the sampling frame

Question 7

give strengths of systematic sampling

Answer 7

• avoids researcher bias
• fairly representative

Question 8

give strengths of systematic sampling

Answer 8

• not truly unbiased unless you use a random number generator first

Question 9

explain stratified sampling

Answer 9

composition of the sample reflects the varying proportions of people in the subgroups (strata) within the wider population
1) identify strata
2) calculate required proportion needed for each strata based on target population
3) select sample at random from each stratum

Question 10

give strengths of stratified sampling

Answer 10

• no researcher bias
• representative data due to proportional strata so can be generalised

Question 10

give limitations of stratfied sampling

Answer 10

• time consuming
• complete representation of target population is not possible as strata cant reflect all differences of wider population

Question 11

give strengths of volunteer sampling

Answer 11

self reflection where ppt offers to take part

Question 11

explain volunteer sampling

Answer 11

• easy and not time consuming
• more likely to coorperate

Question 12

give limitations of volunteer sampling

Answer 12

• volunteer bias - may attract a particular profile of a persin
• motivations like money could mean ppts dont take it seriously