(i) Data: Information in the form of numerical figures is known as data.
(ii) Raw data: Data that is obtained in the original form is known as raw data.
(iii) Array: When the raw data is obtained in ascending or descending order of magnitude, it is known as array.
(iv) Tabulation of data: Arranging the data in a systematic way in the form of a table is known as the tabulation of the data.
(v) Observations: Each numerical figure in a data is known as an observation.
(vi) Frequency of an observation: Number of times an observation occurs in the data is known as the frequency of an observation.
(vii) Statistics: The subject that deals with the collection, presentation, analysis and interpretation of the numerical data is known as statistics.