i) Data based on scale: Based on the scale of measurement, data can be categorised as follows:

• Nominal data
• Ordinal data
• Interval data
• Ratio data

ii) Data based on continuity: Data with reference to continuity can be categorised as follows:

• Continuous data
• Discrete data

iii) Data based on number of characteristics: Data can also be categorised on the basis of number of variables considered. These are:

• Univariate data: Univariate data are obtained when one characteristicis used for observation, e.g., the performance of student in a givenclass.
• Bivariate data: Bivariate data result when instead of one, twocharacteristics are measured simultaneously, e.g., height and weightof tenth class students.
• Multivariate data: Multivariate data consist of observations on threeor more characteristics, e.g., family size, income and savings in a metropolitan city in India.

iv) Data based on time: There are two types of data under this category. These are:

Time series data –Data recorded in a chronological order a cross time are referred to as time series data. It takes different values at different times, e.g., the number of books added to a library in different years, monthly production of steel in a plant, yearly intake of students in a university.

Cross Sectional data – This refers to data for the same unit or for different units at a point of time, e.g., data across sections of people, region or segments of the society.

v) Data according to origin: Data under this category can be put as follows:

Primary data: The data obtained firsthand from individuals by direct observation, counting, and measurement or by interviews or mailing a questionnaire are called primary data.

Secondary data: The data collected initially for the purpose and already published in books or reports but are used later on for some other purpose are referred to as secondary data. For example, data collected from census reports, books, data monographs, etc.

vi) Data according to characteristic: Data can be categorised on the basis of the characteristics as follows:

Quantitative data: When the characteristic of observation is quantified we get quantitative data. Quantitative data result from the measurement of the magnitude of the characteristic used. For example, age of a person, price of a commodity, income of a family, etc.

Qualitative data: When the characteristic of observation is a quality or attribute, we get qualitative data. For example, sex or colour of a person, or intelligence of a student.