Definitions & Data Types

Question 1

What is population?

Answer 1

All of the people or objects that you are interested in analysing

Question 2

What is a sample?

Answer 2

A smaller group of people or objects that we study, taken from the larger population

Question 3

What do we use a sample for?

Answer 3

To understand something about the population

Question 4

What are the problems with using a whole population?

Answer 4

• Expensive
• Time Consuming
• Difficult to contact all members
• Can be impossible in some circumstances

Question 5

What is convenience sampling?

Answer 5

A non-probability technique where subjects are selected because of their convenient accessibility and proximity to the researcher

Question 6

What is random sampling?

Answer 6

Members of the population have an equal chance of being selected

Question 7

What is stratified sampling?

Answer 7

A probability sampling technique wherein the researcher divides the entire population into different sub-groups

e.g. age

and then randomly selects the final subjects proportionally from the different strata

Question 8

What is a variable?

Answer 8

Any attribute which may vary from one person or object in the population to another

e.g. voting intentions in an election

Question 9

What is observation and how is it normally collected?

(in relation to a variable)

Answer 9

The value that a variable has been found to have for a particular person or object

It is usually collected by

• measuring
• counting
• asking questions

e.g. asking someone what their voting intention is

Question 10

What is descriptive statistics?

Answer 10

Using data collected from a group to describe features or draw conclusions about that group

Describes the population that you’re talking about

Question 11

What is inferential statistics?

Answer 11

Using data collected from a sample to describe features or draw conclusions about the population from which the sample was taken

Question 12

What is quantitative data?

Answer 12

Information that can be counted or measured on a numerical scale

A number you can do maths to - just because its a number doesn’t mean that it is quantitative

Question 13

What is qualitative data?

Answer 13

A characteristics or attribute that cannot be described using a numerical value

Question 14

What is coded data?

Answer 14

A number that has no mathmatical significance to it

Question 15

What is discrete data?

Answer 15

Quantitative data that can only take specific numerical values

e.g. no. of houses sold by an estate agent each month

Question 16

What is continuous data?

Answer 16

Quantitative data that can take any numerical value within a specific range

Not a specific number

e.g. weight of cargo being loaded onto a container ship

Question 17

What is nominal level?

Answer 17

Qualitiative data with no natural ordering

e.g. gender of supermarket customers 1=male 2=female

Question 18

What is ordinal level?

Answer 18

Qualitiative data where there is a natural ordering

e.g. size of business - small, medium or large

Question 19

Why should data types be classified before the application of any statistical techniques?

Answer 19

• Can have a big impact on the sort of statistical techniques you use
• The data type will determine which techniques are appropriate for use
  
  • e.g. quantitative or qualitative
• Any conclusions at the end of the investigation will depend on correct classification at the start