Notes On Data Representation - CBSE Class 7 Maths

Any information collected can be first arranged in a frequency distribution table, and this information can be put as a visual representation in the form of pictographs or bar graphs. Data collected is organised in a table for easy understanding and interpreting. Graphs are a visual representation of organised data.

Bar graphs

A bar graph is the representation of data using rectangular bars of uniform width, and with their lengths depending on the frequency and the scale chosen. The bars can be plotted vertically or horizontally. You can look at a bar graph and make deductions about the data.

Bar graphs are used for plotting discrete or discontinuous data, i.e. data that has discrete values and is not continuous. Some examples of discontinuous data are 'shoe size' and 'eye colour', for which you can use a bar chart. On the other hand, examples of continuous data include 'height' and 'weight'.

A bar graph is very useful if you are trying to record certain information, whether the data is continuous or not. Bar graphs can also be used for comparative analysis.

Double bar graphs are used for comparing data between two different things. The difference between a bar graph and a double bar graph is that a bar graph displays one set of data, and a double bar graph compares two different sets of information or data.

Scale of a bar graph
If numbers in units are to be shown in a bar graph, the graph represents one unit of ength for one observation and if it has to show numbers in tens or hundreds, one unit length can represent 10 or 100 observations. This is called the scale of the graph. Length of a bar in a bar  graph depends on the frequency and the scale chosen.

Summary

Any information collected can be first arranged in a frequency distribution table, and this information can be put as a visual representation in the form of pictographs or bar graphs. Data collected is organised in a table for easy understanding and interpreting. Graphs are a visual representation of organised data.

Bar graphs

A bar graph is the representation of data using rectangular bars of uniform width, and with their lengths depending on the frequency and the scale chosen. The bars can be plotted vertically or horizontally. You can look at a bar graph and make deductions about the data.

Bar graphs are used for plotting discrete or discontinuous data, i.e. data that has discrete values and is not continuous. Some examples of discontinuous data are 'shoe size' and 'eye colour', for which you can use a bar chart. On the other hand, examples of continuous data include 'height' and 'weight'.

A bar graph is very useful if you are trying to record certain information, whether the data is continuous or not. Bar graphs can also be used for comparative analysis.

Double bar graphs are used for comparing data between two different things. The difference between a bar graph and a double bar graph is that a bar graph displays one set of data, and a double bar graph compares two different sets of information or data.

Scale of a bar graph
If numbers in units are to be shown in a bar graph, the graph represents one unit of ength for one observation and if it has to show numbers in tens or hundreds, one unit length can represent 10 or 100 observations. This is called the scale of the graph. Length of a bar in a bar  graph depends on the frequency and the scale chosen.

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