1.    Primary sources
Primary sources are raw data without interpretation that represents an official opinion. Examples of primary sources are memos, letters, interviews, laws, regulations, census, etc.

2.    Secondary sources
Secondary sources are interpretations of primary data. Examples of secondary data are encyclopedias, textbooks, handbooks, magazine articles, newspaper articles, etc.

3.    Tertiary sources
Tertiary sources may be interpretations of a secondary source, but generally represented by indexes, bibliographies, and other finding tools such as Internet search engines.

Deduction is a form of argument that intent to be conclusive. The conclusion must necessarily follow from the reasons given.
A deduction is valid if it is not possible for the conclusion to be false if the premises are true.

Induction

In Induction, there is no such strength of relationship between reasons and conclusions.
In Induction, we draw a conclusion from one or more particular facts or pieces of evidence. The conclusion explains the facts, and the facts support the conclusion.

Data mining involves five step processes:
-    Deciding between census and sample data
-    Identifying relationship within the data.
-    Modifying or transforming data.
-    Developing a model that explains the data relationship.
-    Testing the model’s accuracy.

Data in a data warehouse must be continually updated to ensure that decision makers have access to the appropriate data for real-time decisions.

The more accessible the databases in the data warehouse, the more likely a researcher will use them to reveal patterns.