Types of Data

After conducting a research or gathering data from a legitimate source  a data scientist come across a slew of data which are collected from different source & measured on different scales.

This data can be classified..

..Based on Data Source:

The data can be classified as primary or secondary data based on the type of source. 

Primary Data: A primary data is collected from a survey, or focus group interviews,  POS etc. The survey or questionnaire is designed by researcher himself. Hence data collected is very relevant & to-the-point of research objectives.

Secondary Data: While a secondary  data is collected from the legitimate sources like internet sources (like Plunkett research, Business reporter etc) government census, S&P's industry surveys. white books etc, This data is being prepared for general purpose & it sometimes does not make any sense to research objectives, but gives an idea about the macro-environment of the  research study, This data is used as reference in further study.

..Based on Data Type:

When looking at type of data, it can be classified as numeric or categorical data. 

Numeric Data: As name suggest, it comprise of all type of numbers. These data is generally further sub-classified as Continuous data & discrete data. 

Continuous variable is one which can assume any value like 3.45, 12, 6.57e-2 etc. some of the examples are temperature, sensex, etc.

Discrete variable can take particular values as whole numbers. This is most of the time is count and frequency data. 

Categorical Data: A categorical variable can take values which are generally categories, as an example "type of vehicle" is a category & can take values as 2-wheeler, car, heavy vehicle etc. These are the attributes which are further used to sub-classify the data. Sometimes this data can also carry a preference or order attached to each category. Like, the graduation results which are defined on grades as A+, A, B+, B, etc. where a definite order of grade can be assumed. Such as, A+ is better than A, while A is better than B+ and so on.