Y1, C1 - Data Collection

Question 1

What is a population

Answer 1

The whole set of items that are of interest

Question 2

What is a sample

Answer 2

Some subset of the population intended to represent the population

Question 3

What is a sampling unit

Answer 3

Each individual thing in the population can be sampled as a sampling unit

Question 4

What is a sampling frame

Answer 4

Sampling units of a population are individually named to form a list called the sampling frame

Question 5

What is a census

Answer 5

Data collected from the entire population

Question 6

Census advantages and disadvantages (compared to a sample)

Answer 6

+ Completely accurate results
- Time consuming and expensive
- Cannot be used when it involves destruction
- Large volume of data to process

Question 7

Sample advantages and disadvantages (compared to a cenus)

Answer 7

+ Cheaper
+ Quicker
+ Less data to process
- Data may not be accurate
- Data may not be large enough to represent small sub-groups

Question 8

What are the 3 types of random sampling

Answer 8

Simple Random Sampling
Systematic Sampling
Stratified Sampling

Question 9

What is random sampling

Answer 9

Each sampling unit in a sampling frame has an equal chance of being chosen to avoid bias

Question 10

Pros and cons and how to carry out Simple Random Sampling

Answer 10

+ Bias free
+ Easy and cheap
+ Each number has a known chance of being selected
- Not suitable for large population size
- Sampling frame needed
Assign each item an identifying number. Random generator the numbers

Question 11

Pros and cons and how to carry out Systematic Sampling

Answer 11

+ Simple and quick
+ Suitable for large samples
- Sampling frame needed
- Can introduce bias if sampling frame isn’t random
Take every kth elements where k = population size (N) / sample size (n) starting at random item between 1 and k

Question 12

Pros and cons and how to carry out Stratified Sampling

Answer 12

+ Reflects population structure
+ Guarantees proportional representation of groups
- Population must be clearly classified into distinct strata
- Selection within each stratum suffers from same disadvantages as simple random sampling
Same proportion (sample size (n) / population size (N)) from each strata

Question 13

What is a strata

Answer 13

A distinct group

Question 14

What are the 2 types of non-random sampling

Answer 14

Quota sampling
Opportunity / Convenience Sampling

Question 15

What is a quota

Answer 15

A fixed share / number of something

Question 16

When can’t we do a random sample

Answer 16

When we don’t have a sampling frame

Question 17

Pros and cons and how to carry out quota sampling

Answer 17

+ Allows small groups to still be representative of population
+ No sampling frame required
+ Quick, easy, inexpensive
+ Allows for an easy comparison between different groups in population
- Bias
- Population must be divided into groups which can be costly or inaccurate
- Non-responses are not recorded
- Increasing scope of the study increases number of groups therefore time / expense
Stratified sampling but then the interviewer selects the actual sampling units

Question 18

Pros and cons and how to carry out opportunity / convenience sampling

Answer 18

+ Easy to carry out
+ Inexpensive
- Unlikely to provide a representative sample
- Highly dependent on individual researcher
Interviewer selects the actual sampling units according to the set criteria

Question 19

What are the two types of data

Answer 19

Qualitative
Quantitative

Question 20

What is quantitative data

Answer 20

Numerical values

Question 21

What is qualitative / categorical data

Answer 21

Non-numerical values

Question 22

What are the two types of quantitative data

Answer 22

Discrete
Continous

Question 23

What is discrete data

Answer 23

Can only take specific values

Question 24

What is continuous data

Answer 24

Can take any decimal value

Question 25

What is a trace value (tr)

Answer 25

When the value is too low to be measured (under the minimum measuring unit, e.g. under 1cm on a metre ruler)