Year 1 Statistics

Question 1

Target Population

Answer 1

All the members of the population you would ideally like to get the information from (population of interest)

Question 2

Census

Answer 2

When the whole target population is investigated

Question 3

Sample

Answer 3

A small part or quantity intended to show what the whole population is like

Question 4

Bias

Answer 4

A systematic error

Question 5

Sampling frame

Answer 5

List of the target population

Question 6

Simple random sampling

Answer 6

Every possible sample of given size is equally likely to be selected

Question 7

Advantages of simple random sampling

Answer 7

Representative if the sampling frame is available
Quick and easy to use

Question 8

Cluster sampling

Answer 8

The target population is divided into naturally occurring subgroups and a sample of the clusters is then taken

Question 9

Systematic sampling

Answer 9

Choose a starting point at random then systematically take objects at a certain number apart

Question 10

Stratified sampling

Answer 10

The target population us divided into groups based on characteristics - called strata

Question 11

Proportional stratified sampling

Answer 11

The frequencies for each group un the sample are proportional to the frequencies for each group in the target population

Question 12

Quota sampling

Answer 12

Split population into strata then judgement is used to select members from each group

Question 13

Opportunity sampling

Answer 13

uses people form the target population available at the time and willing to take part

Question 14

self-selecting sampling

Answer 14

Individuals have chosen to be in the sample

Question 15

Disadvantages of simple random

Answer 15

• Not possible without a sampling frame
• Potentially time consuming, disruptive and expensive
• There may be missing values in the sample

Question 16

Cluster sampling advantages

Answer 16

• Convenient
• Doesn’t need a sampling frame for the population
• Samples from different areas

Question 17

Cluster disadvantages

Answer 17

• Non-random
• May be overlap in the clusters

Question 18

Systematic Advantages

Answer 18

• Representative if the sampling frame is available
• Can be quick and easy to use

Question 19

Systematics disadvantages

Answer 19

• Not possible without a sampling frame
• If the sampling frame coincides with a periodic trait in the population the sampling technique will no longer be random or representative, introducing bias
• There may be missing values in the sample

Question 20

Stratified sampling advantages

Answer 20

• Representative if the sampling frame is available
• The frequencies for each group in the sample can be proportional to the frequencies for each group in the population

Question 21

Stratified sampling disadvantages

Answer 21

-Not possible without a sampling frame
- Strata must be carefully defined
Sometimes difficult to split the population into naturally occurring groups
-There may be missing values in the sample

Question 22

Quota advantages

Answer 22

• Doesn’t need a sampling frame
• The frequencies for each group in the sample can be proportional to the frequencies for each group in the population

Question 23

Quota disadvantages

Answer 23

-Non-random
- May not be representative of the target population and could be biased

Question 24

Opportunity advantages

Answer 24

• Quick and easy
• Convenient

Question 25

Opportunity sampling disadvantages

Answer 25

• Non-random
• May not be representative of the target population and could be biased

Question 26

Self-selecting sampling advantages

Answer 26

• Quick and easy
• Convenient

Question 27

Self-selecting sampling disadvantages

Answer 27

• Non-random
• May not be representative of the target population and could be biased

Question 28

Categorical/Qualitative

Answer 28

Values that are names or labels. Split into Nominal (no order) or Ordinal (ranked)

Question 29

Numerical/Quantitative

Answer 29

Values that are a measured quantity. Split into discrete and continuous data.