Statistics

Question 1

Define Qualitative

Answer 1

Data that is descriptive - uses words

Question 2

Define Discrete Quantitative

Answer 2

Data that can be counted (number of plants in a field)

Question 3

Define Continuous Quantitative

Answer 3

Data that can be measured (height of plant - ongoing)

Question 4

Define Population

Answer 4

All the individuals you are interested in for a particular investigation

Question 5

Define Census

Answer 5

Collecting data from the whole population

Question 6

Advantages of a census

Answer 6

Should be completely accurate

Question 7

Disadvantages of a census

Answer 7

• Time consuming
• Expensive
• Hard to process large quantity of data

Question 8

Define Sample

Answer 8

Collecting data from part of the population

Question 9

Advantages of sample

Answer 9

• Quick
• Cheap
• Less data to process

Question 10

Disadvantages of sample

Answer 10

• Data may not be accurate

- Sample may not be large enough to give information about small sub-groups of the population

Question 11

Define Simple Random Sampling

Answer 11

Every member of the population has an equal chance of being picked

Question 12

Simple Random Sampling pros and cons

Answer 12

Pros:
- Free of Bias
- Easy and cheap to implement for small populations
Cons:
- Not suitable for a large sample size
- A sampling frame is needed

Question 13

Define Systematic Sampling

Answer 13

The required elements are chosen at regular intervals from an ordered list

Question 14

Systematic Sampling pros and cons

Answer 14

Pros:
- Simple and quick to use
- Suitable for large samples and large populations
Cons:
- A sampling frame is needed
- Can introduce bias

Question 15

Define Stratified Sampling

Answer 15

Population divided into groups based on age, gender, etc. and a random sample is taken from each

Question 16

Stratified Sampling pros and cons

Answer 16

Pros:
- Accurately reflects the population structure
- Guarantees proportional representation of groups within population
Cons:
- Population must be clearly classified into distinct strata

Question 17

Define Quota Sampling

Answer 17

The researcher selects a sample that reflects the characteristics of the whole population

Question 18

Quota Sampling pros and cons

Answer 18

Pros:
- No sampling frame needed
- Quick, easy and cheap
- Allows for easy comparison between different groups within a population
Cons:
- Could introduce bias
- Population must be clearly classified into distinct strata which can be inaccurate

Question 19

Define opportunity sampling

Answer 19

Individuals chosen to be part of a sample as the opportunity arises

Question 20

Opportunity Sampling pros and cons

Answer 20

Pros:
- Easy to carry out
- Inexpensive
Cons:
- Unlikely to provide a representative sample

Question 21

Explain what is meant by stratified sampling and why it is used (4 marks)

Answer 21

• There are identifiable strata that may exhibit different characteristics
• Each stratum is randomly sampled
• Use it to obtain a representative sample
• Can use it to get information on the individual strata