(4) SAMPLING

Question 1

Define population, sample and representative

Answer 1

POPULATION - a group of ppl who are the focus of the researcher’s interests, from which a smaller sample is taken

SAMPLE - a group of people taking part in an experiment

REPRESENTATIVE - if a sample correctly represents a population

Question 2

Define random sampling and state the pros and cons

Answer 2

• Random sampling
○ Definition
§ Everyone = equal chance to be selected
§ Compile names of all target population and randomly generate the names
□ Eg pick out of hat, random word generator
○ PROS
§ Researcher bias eliminated
□ Ppl randomly selected so researcher doesn’t pick ppl they think will confirm their hypothesis
○ CONS
§ Not time efficient - complete list of target population hard to obtain
§ Sample could be unrepresentative
□ Eg if u get 25 girls and 5 boys in a population of 100 students

Question 3

Define systematic sampling and give the pros and cons

Answer 3

• Systematic sampling
○ Definition
§ List of ppl within target population is produced
§ Every nth participant (eg 5th, 7th) on the list is included in experiment
○ PROS
§ No researcher bias - they don’t know who those nth people are
○ CONS
§ Every nth person could have things in common
□ Unrepresentative

Question 4

Define stratified sampling and give the pros and cons

Answer 4

• Stratified sampling
○ Definition
§ People are selected to exactly represent the target population
§ Divide target pop. Into subcategories
§ Select members in proportion that they occur in population
□ Eg if u have a pop. Of 200 people, 60% are boys and 40% girls and you need 10 participants, 6 should be boys and 4 girls
§ To meet required number, participants selected by random sampling
□ Eg continuing from last example, out of all 60% boys and 40% girls, they will be picked at random but you still end up with 6 boys and 4 girls
○ PROS
§ Avoids researcher bias
§ Well representative
○ CONS
§ Very expensive and time consuming
§ Not perfect, subcategories wont reflect all individual differences

Question 5

What is opportunity sampling and give the pros and cons

Answer 5

• Opportunity sampling
○ Definition
§ When you use a sample that is available and willing to participate
○ PROS
§ Quick & easy so convenient
○ CONS
§ Unrepresentative
§ Researcher bias - they control who is selected

Question 6

What is volunteer sampling and give the pros and cons

Answer 6

• Volunteer sampling
○ Definition
§ Self selection - participants involve themselves in project
○ PROS
§ Very easy as people come to you - convenient
○ CONS
§ Volunteer bias - may attract a certain type of person