Sample
A selection from the whole population
Primary Data
Data which is collected for a specific investigation
Standard Deviation
Square root of variance
Qualitative Data
Data which can be organised into categories but cannot be given a numerical value
Lower Quartile
The item one quarter of the way through when the data are put in order
Continuous data
Data which can be measured and which can take any value within a certain range
Discrete data
Data which can have only certain definite values
Mode
The most common
Median
The middle item when the data are in order
Secondary data
Data which is already published and which may be accessed for many investigations
Quantitative data
Data which can be measured or which has an exact numerical value
Interquartile Range
Upper quartile - Lower quartile
Upper quartile
The item three quarters of the way through when the data are put in order
Standard deviation
Tells us how much the data spread out around the mean
Mean
A measure of the average which uses all the data values
Range
The difference between the largest and smallest data values
Population
The whole group that we are interested in
Interquartlie range
Tells us the spread of the middle 50% of the data values
