Data interpretation line graph

Data Interpretation line graph

Line graph data interpretation questions are asked in various competitive exams like SSC, IBPS clerk mains, SBI PO prelims, RRB, etc., all the concepts of line graph in Data Interpretation are explained from basics with example questions and solution below. By learning the concepts and practicing different types of data interpretation line graph tricks, questions help in mastering the line graph topics.

What is the data interpretation line graph?

An updated version of the bar chart is a line graph. Usually, by joining the uppermost points of the bars we can form a line. Similarly, with other bars repeating the same process we can form a line chart.

Line graphs are progressively self-evident, exact and precise than graphs. Line graphs are very useful for determining trends, to study slopes, rates of change and for illustrating comparisons with respect to some time series.

Construction of a line graph

Line graphs are represented on a special kind of paper called Graph Paper. This graph paper consists of various horizontal and vertical lines that form a number of squares inside the graph paper consist of two straight lines drawn at right angles intersecting each other at a point ‘o’ as shown in the figure. This point is called the origin.

The horizontal line is called x-axis represented by xox’. The distance measured from the right side of origin is considered as positive and distance measured left side of origin is taken as negative.

The vertical line is called the y-axis represented by yoy’. Here distance measured from the top side of origin is considered from origin to bottom is considered as negative from the graph we can see from quadrants formed by intersecting x-axis and y-axis.

Generally, for line graph in Data interpretation, we consider the first quadrant which is always positive unless negative quantities are given.

Data Interpretation line graph

The pair of variables represented on the graph are denoted as (x , y). Here x is the value of an independent variable (x-coordinate) and y is the value of the dependent variable (y-coordinate).

Generally, line graphs show how a quantity of dependent variable changes with the value of the independent variable.

As there are represented on x-y axis line graphs are also called x-y charts. Data represented on x-y co-ordinates may be in different forms based on time series like years, half-year, quarter, month, week, hour, day etc.

Generally, dates related to economics and business will be in the form of time series. Let’s see various types of data representations that are possible to determine on x-y coordinates in line graph data interpretation.

Types of graphs by data representation in the line graph (time series):

  1. Single dependent. Variable line graph

Over a certain period of time, these graphs show changes in a single variable.

  1. More than one dependent variable line graph:

For representing two or more dependent variables these graphs show two or more lines.

  1. Speed time graph:

This is a special case in line graph where the speed of a body against time is shown on respective axes.


Data interpretation line graph example with solution

Given below is a line graph represents data related to imports and exports of a company in the months of Jan to June(rupees in lacks). Observe the data given in the graph carefully and answer the questions asked.

Data Interpretation line chart


  1. What was the average import from Jan to June?

All the imports of the company month-wise are (in lacks)

Average import from Jan to June =sum of total imports (in lacks)/number of months import done

  1. Percentage decrease in exports from April to May

Exports of the company in the months of April are 7.5 lacks.
Exports of the company in the month of May are 12.5 lacks.
Percentage decrease in exports=(12.5-7.5/7.5)×100

  1. What was the difference in export between February and March?

The exports of the company in February are 7.5 lacks.
The exports of the company in March are 17.5 lacks.
The difference in exports between February and March is (12.5-7.5) lack= 5 lacks

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