tolentino_displaying data (graphs)

8/8/2019 Tolentino_Displaying Data (Graphs)

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Displaying DataGraphsPrepared by Inah GeneveTolentino


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Graphs

A graph is based on the tabled data andtherefore can tell no story that cannot be

learned by inspecting a table. However,graphic representations often makes it easierto see the pertinent features of a set of data(Minium 1978: 45).

Device showing numerical values orrelationships on pictorial form


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Graphs can be constructed on any

of the following: Types of data

Qualitative

Quantitative

Types of variable

Nominal

Ordinal

Interval

Ratio


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Important Points in Constructing a

Graph Two axes: Abscissa (horizontal) and

Ordinate (vertical)

Represent the subcategories of the variable

along the X-axis Represent the frequency or count of that

subcategory along the X-axis

Zero point (intersection) Starting point


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Important Points in Constructing a

Graph Put a title on the graph and label the axes. Describing its contents/what it represents

Use an appropriate scale.

There are different types of graph and thekind that you will use shall be based on

the type of data you are displaying.

Categorical Variablescharts or histograms Continuous Variablesline or trend graphs


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Set of data to be used for some of the sample graphs:


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The Histogram

A series of rectangles drawn next to each

other without any space between them,

each representing the frequency of a

category or subcategory

For both categorical and continuous


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The Bar Chart

Identical to a histogram, except that in a

bar chart the rectangles representing the

various frequencies are spaced, thus

indicating that the data is categorical.

For nominal and ordinal scales


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The Bar Chart

STACKED BAR CHART

A bar chart wherein each bar shows

information about two or more variables

stacked onto each other vertically.

100 PER CENT BAR CHART

The subcategories of a variable for a

particular bar total 100 per cent and eachbar is sliced into portions related to their

proportion.


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The Frequency Polygon

Drawn by joining the midpoint of eachrectangle at a height commensurate with thefrequency of that interval (class mark)

Should always be a closed figure

CUMULATIVE FREQUENCY POLYGON

Drawn on the basis of cumulative

frequenciesJoining the endpoints of the intervals (class

boundary)


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The stem-and-leaf display

An effective, quick and simple way ofdisplaying a frequency distribution.

By rotating the SALD 90 degrees

counterclockwise, a histogram will result.


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The Pie Chart

Another way of representing datagraphically, this is as a circle.

Pieces of the pie representing the

portions of the total that fall under eachcategory.


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The Line Diagram or Trend Curve

Displaying a set of data on a continuousinterval or a ratio scale

Specific time (long term trends)

represented by the straight line

Specific period(trends in a phenomenon)

represented by the dotted line (at

midpoints)

E.g. Birth rates, changes in population, and

death rates


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The Area Chart

Plotting of values is the same as the linediagram with the area under each line

shaded to highlight the magnitude of the

subcategory in relation to othersubcategories.


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The Scattergram

Showing how one variable changes inrelation to a change in the other variable


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Respondent Income Age

A 25500 24

B 46000 50

C 30500 36

D 55000 45

E 27000 29

F 35000 38

G 40000 37

H 52000 48

I 47000 41

J 38000 47

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