Data Collection

Question 1

Define ‘population’.

Answer 1

The whole set of items that are of interest.

Question 2

Define ‘census’.

Answer 2

A study of every member of the population.

Question 3

Define ‘sample’.

Answer 3

A study of a subset of a population which is used to find out information about the whole population.

Question 4

Give an advantage of a census.

Answer 4

It should give a completely accurate result.

Question 5

Give three disadvantages of a census.

Answer 5

1) Time consuming and expensive
2) Cannot be used when the testing process destroys the item
3) Hard to process a large quantity of data

Question 6

Give three advantages of a sample.

Answer 6

1) Less time consuming and expensive
2) Fewer people have to respond
3) Less data to process

Question 7

Give two disadvantages of a sample.

Answer 7

1) The data may not be as accurate
2) The sample may not be large enough to give information about small sub-sections of the population

Question 8

Define ‘sampling unit’.

Answer 8

An individual unit of a population.

Question 9

Define ‘sampling frame’.

Answer 9

A list of individually named/numbered sampling units.

Question 10

Define ‘simple random sampling’.

Answer 10

A sample where every unit has an equal chance of being selected.

Question 11

Define ‘systematic sampling’.

Answer 11

A sample where the required elements are chosen at intervals from an ordered list.

Question 12

Define ‘stratified sampling’.

Answer 12

A sample where the population is divided into mutually excused strata and a random sample is taken from each.

Question 13

Give three advantages of simple random sampling.

Answer 13

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

Question 14

Give two disadvantages of simple random sampling.

Answer 14

1) Not suitable when the population or sample size is large as it is potentially time consuming, disruptive and expensive
2) A sampling frame is needed

Question 15

Give two advantages of systematic sampling.

Answer 15

1) Simple and quick to use
2) Suitable for large samples and large population

Question 16

Give two disadvantages of systematic sampling.

Answer 16

1) A sampling frame is needed
2) It can introduce bias if the sampling frame is not random

Question 17

Give two advantages of stratified sampling.

Answer 17

1) Sample accurately reflects the population structure
2) Guarantees proportional representation of groups within a population

Question 18

Give two disadvantages of stratified sampling.

Answer 18

1) Population must be clearly classified into distinct strata
2) Selection within each stratum suffers from the same disadvantages as simple random sampling

Question 19

Define ‘quota sampling’.

Answer 19

A survey that uses a sample that reflects the characteristics of the whole population.

Question 20

Define ‘opportunity/convenience sampling’.

Answer 20

A survey that uses a sample from people who are available at the right time and fit the criteria you are looking for.

Question 21

Give four advantages of quota sampling.

Answer 21

1) Allows a small sample to still be representative of the population
2) No sampling frame required
3) Quick, easy, and inexpensive
4) Allows for easy comparison between different groups within a population

Question 22

Give four disadvantages of quota sampling.

Answer 22

1) Non-random sampling can introduce bias
2) Population must be divided into groups, which can be costly or inaccurate
3) Increasing scope increases the number of groups, adding time and expense
4) Non-responses are not recorded as such

Question 23

Give two advantages of opportunity sampling.

Answer 23

1) Easy to carry out
2) Inexpensive

Question 24

Give two disadvantages of opportunity sampling.

Answer 24

1) Unlikely to provide a representative sample
2) Highly dependent on individual research

Question 25

Define ‘quantitative’.

Answer 25

Variables or data associated with numerical observations.

Question 26

Define ‘qualitative’.

Answer 26

Variables or data associated with non-numerical observations

Question 27

Define ‘continuous’.

Answer 27

A variable that can take any value in a given range.

Question 28

Define ‘discrete’.

Answer 28

A variable that can take only specific values in a given range.