Page 295 - ICSE Math 8

GRAPHICAL REPRESENTATION OF DATA

Term Definition Formula/Example

Raw Data Non-meaningful collection of Marks obtained by students of a class
information

Array/Arranged Data Data arranged in ascending/
descending order

Discrete Data Data that has only whole number Number of students in 4 classes: 20, 25,
values 32, 38.

Continuous Data Data that can have any values Height of students: 146 cm, 152.50 cm,
etc.

Range Greatest value – Smallest value Number of students in 5 classes: 20, 25,
25, 32, 38. Then, Range = 38 – 20 = 18
Frequency Number of times a particular In the above data, 25 occurs twice. So, its
observation occurs in a data frequency = 2
Tally marks Used to mark frequencies in Symbol: = 1, = 2, = 3, = 4, = 5
groups of five
Class Interval (CI)/Class size Difference between two successive For class intervals 1–20, 21– 40, etc., the
lower class limits or two class interval is 21 – 1 or 40 – 20 which
successive upper class limits is 20.

Exclusive (or continuous) CI The upper limit of one class is the 0–10, 10–20, 20–30, etc.
lower limit of the next class

Inclusive (or discontinuous) CI The upper limit of one class is not 0–4, 5–9, 10–14, etc.
the lower limit of the next class

Inclusive to Exclusive conversion If a – b = inclusive class interval
Corresponding Exclusive CI = a −   h  −   b − h  ;
 2   2 
h = (Lower limit of a class) – (Upper limit of previous class)
Class Mark Mid-value of a class interval (Upper limit + Lower limit)
2

Bar Graph Pictorial representation of numerical data in the form of rectangles (or bars) of
equal width and varying heights

Pie Chart Pictorial representation of numerical data in a circle divided into sectors

Central angle of a component  Value of the component 
  × 360°
 Total value of all the components 

Value of a component (Central angle of the component × total of the component values)
360

% value of a component (Central angle of the component × 100)
360°

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