Data structure

Context is critically important, but the statistical methods that can be used on data depend mostly on the internal structure of the data.

Employees
 Gender   Age 
Male
Male
Male
Male
Male
Male
Female
Female
Female
Female
Female
Female
62
46
51
29
44
30
52
55
28
63
41
33
Telephone survey
Location
 of district 
Response
rate
Rural
Rural
Rural
Rural
Rural
Rural
Urban
Urban
Urban
Urban
Urban
Urban
62
46
51
29
44
30
52
55
28
63
41
33
Camp site use on 12 days
Weather Number
of tents
Dry
Dry
Dry
Dry
Dry
Dry
Wet
Wet
Wet
Wet
Wet
Wet
62
46
51
29
44
30
52
55
28
63
41
33

These three data sets have the same basic structure, so the same statistical methods can be applied to all of them.

Variables and 'individuals'

Most data sets have a fairly simple structure. One or more measurements ('variables') are recorded from each of a collection of 'individuals' (also called 'cases' or 'units'). The data can be presented in a data matrix.