GCSE Statistics - collecting data terms

Raw Data

Data just as it is collected - before it is ordered or grouped.

Can be either quantitative or qualitative.

Quantitative Data

Numerical observations or measurements.

* Numbers
* Is either continuous or discrete

Qualitative Data

Non - numerical observations.

* Often words

Continuous Data

Can take any value on a continuous numerical state.

* e.g. measurements

Discrete Data

Can only take particular values on numerical scale

• shoe size or number of pets

Ordinal Data

Can be written in order or can be given a numerical rating scale.

Bivariate Data

Involves pairs of related data.

Multivariate Data

Involves sets of 3 or more related data values.

Primary Data

Data collected by or for the person who is going to use it.

Secondary Data

Data collected by someone else

Population

Everything or everybody that could be involved in an investigation

Census

A survey or investigation with data taken from every member of a population

Sample

Contains information about part of a population. The results can be used to make conclusions for the whole population.

Hypothesis

An idea that can be tested by collecting and analysing data.

* Should be a statement not a question
* Needs to be precise about something you can measure.

Explanatory or Independent Variable

What a researcher changes

Response or Dependant Variable

Is affected by the explanatory variable

Extraneous Variable

Need to be controlled, could affect results of the experiment

Field experiments

Carried out in an everyday (uncontrolled) environment. Researcher sets up the situation and variables are controlled.

Natural experiments

Carried out in an everyday (uncontrolled) environment. The researcher has no control over any variables.