What is raw data?
Unprocessed data that has just been collected
What is qualitative data?
Non-numerical, descriptive data (e.g. eye colour)
What is quantitative data?
Numerical, measured data (e.g. height)
What is discrete data?
Quantitative data that can only take certain values (e.g. shoe size)
What is continuous data?
Quantitative data that takes any value (e.g. weight)
What is nominal data?
Qualitative data that consists of no natural order (e.g. blood groups)
What is an ordinal scale?
Data that can be given an order, rank, or rating (e.g. grades)
What is bivariate data?
Any data involving two measurable variables: the explanatory and response variables (often represented using scatter graphs)
What is multivariate data?
Any data involving more than two variables
What is a categorical scale?
Qualitative data sorted into classes with names or numbers so that data can be easily processed
What is the explanatory variable?
The variable that causes change in something else, placed on the x-axis
What is the response variable?
The variable used to measure the effect of changing the explanatory variable, placed on the y-axis
Which sampling techniques are non-random? (4)
- judgement
- opportunity
- quota
- systematic
Which sampling techniques are random?
- simple random
- stratified
- cluster
What is cluster sampling?
A cluster of the population (e.g. a housing estate) is randomly chosen and people within it are studied.
What is stratified sampling?
Taking samples from defined groups (stratas) at the correct proportion to the population.
What is opportunity sampling?
Selecting the most accessible part of the population present at one particular place and time.
What is judgement sampling?
Selecting people who seem the most representative of their population.
What is systematic sampling?
Choosing a random starting point and taking samples at regular intervals afterwards.
What is simple random sampling?
Sampling a population where everyone has an equal (non-zero) chance to be selected.
What is quota sampling?
Sampling a specified target number of people in each group of the population.
