Sampling

Question 1

Random

Answer 1

Gives all members of target population an equal chance of being selected. Each name given a number then using lottery method picked out the pps.

Question 2

R Strengths

Answer 2

Potentially unbiased as EVs should be equally divided so high internal validity.
Most likely to be representative of target population.

Question 3

R Weaknesses

Answer 3

Difficult and time consuming (obtaining full list of names).
Not guaranteed to be representative as can refuse to take part leading to volunteer sample.

Question 4

Systematic

Answer 4

Pre-determined system e.g. every nth number from list of target population names until required number.

Question 5

S Strengths

Answer 5

Assuming list order randomised it is objective.
Offers unbiased chance of getting representative sample.

Question 6

S Weaknesses

Answer 6

Time consuming.
List assembled wrong, bias present.
Not guaranteed to be representative as can refuse to take part leading to volunteer sample.

Question 7

Opportunity

Answer 7

Uses people who are available at time of study being carried out and fit criteria.

Question 8

O Strengths

Answer 8

Quick, easy, and inexpensive.

Question 9

O Weaknesses

Answer 9

Bias as unrepresentative sample of target population so not generalisable.
Researcher bias present as they select pps.
Not guaranteed to be representative as can refuse to take part leading to volunteer sample.

Question 10

Stratified

Answer 10

Ensures every strata within target population or wider population are represented. They identify strata, work out percentage that strata makes up the population, randomly sample participants to reach that same percentage.

Question 11

Calculation for percentage strata makes up

Answer 11

(sample size/target population)*number in strata

Question 12

St Strengths

Answer 12

Avoids problem of misrepresentation.
Produces representative sample so generalisable.

Question 13

St Weaknesses

Answer 13

Takes more time and resources to plan.
A lot of care taken to ensure key characteristics present or else bias is not fully possible.
Not guaranteed to be representative as can refuse to take part leading to volunteer sample.

Question 14

Volunteer

Answer 14

Sample allows pps who actively want to participate, take part.

Question 15

V Strengths

Answer 15

Quick, easy, and inexpensive.
Achieves large sample size through reaching wider audience.

Question 16

V Weaknesses

Answer 16

Volunteer bias.
Unlikely to get representative sample.