SAMPS & POPS

Question 1

Population

Answer 1

Large number of people researcher interested in studying.

Question 2

Sample

Answer 2

Smaller group taken from pop - not usually possible to study all members of pop

Question 3

Generalisation

Answer 3

Sample should be representative of pop so generalisations can be made

Question 4

Bias

Answer 4

e.g. groups under/over represented

Question 5

1. OPPORTUNITY SAMPLING

Answer 5

• uses people who are nearest / easiest to obtain

Question 6

2. STRATIFIED SAMPLING

Answer 6

Pps selected according to their frequency in a target pop.

Subgroups (or ‘strata’) are identified e.g. gender / age group. The relative percentages of the subgroups in the population are reflected in the sample.

Question 7

Advantage of opportunity sampling?

Answer 7

Convenient, easy technique, less time consuming,

popular technique

Question 8

4. SYSTEMATIC SAMPLING

Answer 8

Pps selected using a sampling frame e.g. a set pattern - e.g. every 7th person on a list of the target pop.

Question 9

5. SNOWBALL SAMPLING

Answer 9

pps asked to assist researchers in identifying other potential subjects

Question 10

6. RANDOM SAMPLING

Answer 10

Every person in target pop has equal chance of being selected. Lottery method - all individuals in target pop numbered, placed in a tombola.

Question 11

Advantage of random sampling?

Answer 11

Potentially unbiased - researcher has no influence over who is selected - free from researcher bias

Question 12

Disadvantage of random sampling?

Answer 12

Representation not guaranteed - could still produce a biased sample. Limits ability to generalise.

Question 13

Advantage of systematic sampling?

Answer 13

Unbiased - first item usually selected at random. Objective method.

Question 14

Disadvantage of systematic sampling?

Answer 14

Time consuming, takes lots more effort. May as well use random sampling

Question 15

Advantage of stratified sampling?

Answer 15

Characteristics of target pop are represented. More likely to be generalisable.

Question 16

Disadvantage of stratified sampling?

Answer 16

Complete representation impossible - strata cannot reflect all ways in which people are different.