Chapter 1 - Data Collection

Question 1

Census

Answer 1

A census observes or measure every member of a population

Question 2

Advantage of Census

Answer 2

It should give a completely accurate result

Question 3

Disadvantages of census

Answer 3

• Time consuming and expensive
• Cannot be used when testing process destroys the item
• Hard to process large quantity of data

Question 4

Sample

Answer 4

A sample is a selection of observations taken from a subset of the population which is used to find out information about the population as a whole

Question 5

Advantage of sample

Answer 5

• Less time consuming and expensive than a census
• Fewer people have to respond
• Less data to process than in a census

Question 6

Disadvantage of sample

Answer 6

• The data may not be as accurate

- The sample may not be large enough to give information about small sub group of the population

Question 7

Simple random sample

Answer 7

A simple random sample of size n is one where every sample of size n has an equal chance of being selected

Question 8

Advantage of simple random sampling

Answer 8

• Free of bias
• Easy and cheap to implement for small populations and small samples
• Each sampling unit has a known and equal chance of selection

Question 9

Disadvantage of simple random sampling

Answer 9

• A sampling frame is needed

Question 10

Advantage of Systematic sampling

Answer 10

• Simple and quick to use

- Suitable for large sample and large populations

Question 11

Disadvantage of systematic sampling

Answer 11

• A sampling frame is needed

- It can introduce bias is the sampling frame is not random

Question 12

Advantage of stratified sampling

Answer 12

• Sample accurately reflects the population structure

- Guarantees proportional representation of groups within a population

Question 13

Disadvantage of stratified sampling

Answer 13

• Population must be clearly classified into distinct strata

- Selection within each stratum suffers from the same disadvantage as simple random sampling

Question 14

Quota sampling

Answer 14

Quota sampling, an interviewer or researcher selects a sample that reflects the characteristics of the whole population

Question 15

Opportunity sampling

Answer 15

Opportunity sampling consists of taking the sample from people who are available at the time the study is carried out and who fit the criteria you looking for.

Question 16

Advantage of quota sampling

Answer 16

• No sampling frame required
• Quick, easy and inexpensive
• Allows for easy comparison between different groups within a population

Question 17

Disadvantage of Quota Sampling

Answer 17

• Non- random sampling can introduce bias
• Non - responses are not recorded as such
• Population must be divided into groups, which can be costly or inaccurate

Question 18

Advantage of Opportunity sampling

Answer 18

• Easy to carry out

- Inexpensive

Question 19

Disadvantage of opportunity sampling

Answer 19

• Unlikely to provide a representative sample

- Highly dependent on individuals researches