Presentation of data — Statistics STD 11 Commerce — Question

The classification of numeric data is called numerical classification or quantitative Classification.

• Illustration : If the data are collected on ‘printing mistakes per page’ of a book of 50 pages, then 50 observations on ‘printing mistakes per page’ are obtained. Studying this ungrouped data it is observed that there are 10 pages having 0 printing mistake, 18 pages having 1 printing mistake, 10 pages having 2 printing mistakes and 12 pages having 2 printing mistakes. Thus, the process of dividing the data in this manner is called numerical classification, which can be presented in tabular form as follows :

No. of printing mistakes per page	0	1	2	3	Total no. of pages
No. of pages	10	18	10	12	50

Here, ‘Number of printing mistakes per page’ is numeric variable. Hence, classification mentioned above is called numerical classification.

• The frequency table is formed by numerical classification of the data.
• Numeric variable may be discrete or continuous.

Therefore, we get discrete frequency table or continuous frequency table by numerical classification of the data.