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KLU - RM - Unit-3 Graphic Presentation (Graph (graphic presentation of…
KLU - RM - Unit-3 Graphic Presentation
Graph
graphic presentation of data.
A graph is the geometrical image of a data.
A graph is a diagram consisting of lines of statistical data.
The graph is drawn on a
graph paper
.
The graph has two intersecting lines called
axes
.
The horizontal line is called
X-axis
.
The vertical line is called
Y-axis
.
The point of intersection is called '
O
'
Graph Types
Time series graphs
Graph of one variable
When only one variable is to be represented on the X-axis
graph showing fish landing in a pond (x-axis - Months)
Graph of two or more variables
we can represent two or more variables on the same graph.
Yeild of grains in tonnes for 6 years (x-axis - years; y-axis - grains: wheat;pulses;paddy)
Range chart
used to exhibit min & max values of a variable.
high and low temp for the 5 days. x-axis: Days & y-axis: temp (deg c)
Band graph / Layer Chart
the various component parts are represented in the form of bands one above the other.
showing the production of paddy, wheat and chillies; x-axis: Year; y-axis: production in million Tonnes.
False Base Line
The graphs containing data that vary with time are called
time series data
.
Frequency distribution graphs
Histogram
It is a graph containing frequencies in the form of vertical rectangles. It is an area diagram.
It is a graphical presentation of frequency distribution
x-axis is class intervals and y-axis is frequencies
It is a two dimensional diagram.
Uses of Histogram/polygon
It gives a clear picture of the entire data
It simplifies a complex data
It is attractive and impressive
It is easily memorized
Median and mode can be located
It facilitates comparison of two or more frequency distribution on the same graph.
It gives an idea of the pattern of distribution of variables in the population.
Frequency polygon
Polygon is a histogram with straight lines joining the midpoints of the top of the rectangles.
Polygon means a figure with many angles.
The height if each rectangle is equal to the frequency of each class.
The midpoints of the top of the rectangles are joined by
straight lines
.
Frequency curve
Uses of Frequency Curve
It is a graph of frequency distribution where the line is smooth.
A histogram is drawn. The midpoints of the top of the rectangles are joined by a
smooth line
.
frequency curve is divided into 3 types
Normal distribution curve
Positively skewed distribution curve.
negatively skewed distribution curve.
Ogives (Cumulative Frequency Curve)
When cumulative frequencies are plotted on a graph, then the frequency curve obtained is called "
Ogive
" or
cumulative frequency curve
Two Types
Less than Ogive or Less than Cumulative Frequency Curve / rising curve
More than Ogive or More than Cumulative Frequency curve / declining curve
Utility
To determine the number of cases above or below a given value.
To compare two or more frequency distribution
To determine certain values graphically such as median, quartiles, etc.
Graphs obtained by plotting grouped data are called
frequency distribution graphs
.
Prepared by: Srinivas Adapa (183030001)