2. Statistics includes collection and analysis of data.
Presentation of the collected information in an attractive and
informative form is also an important function of statistics.
Tabular presentation is one form of presenting data.
But people have more affinity towards pictures or diagrams.
3. Data which fall into different categories or qualitative classes
is called categorical data.
EXAMPLES:
Observations on geographical or chronological
characteristics like populations of different countries
Population of a country in different years
Amounts spents or different items of expenditure by a
family etc.
4. One dimensional diagrams like bar diagrams.
Two dimensional diagrams like rectangles, squares and
circles.
Three dimensional diagrams like cubes, cylinders and spheres.
Pictograms and cartograms.
5. These are the most commonly used diagrams.
Horizontal or vertical lines or bars with their lengths
proportional to the magnitude of the observations
corresponding to each category constitute this diagram.
Bars are preffered to lines as their thickness attracts the
attention.
Bars are drawn with the same width and at equal distances
This type of diagram is called a bar diagram.
6. 1. Simple bar diagrams
2. Sub divided or component bar diagrams
3. Percentage bar diagrams
4. Multiple bar diagrams
5. Deviation bar diagrams
7. Horizontal or vertical bars with the same width, drawn with
their bases on the same horizontal or vertical line with equal
gaps in between
length proportional to the magnitude of the observations
constitute a bar diagram.
This diagram is used when the data is in the form of
observations corresponding to different categories.
8. Country India U.SA. Italy Egypt Japan
Yield in kgs per
hectre
728 1469 2903 2153 2276
0
500
1000
1500
2000
2500
3000
3500
India U.S.A Italy Egypt Japan
9. Used when the observations corresponding to the various categories have
different components
When comparison of the component parts is important.
Simple bar diagram is drawn first with the length of the bars proportional
to the totals of the component parts.
Subdivided into parts of length proportional to the component magnitudes.
Each part given a different color or shading.
Eg: The growth of production of fish for the period 1996-97 to 2002-03 is
given below:
11. This is a modification of the component bar diagram.
It is used when comparison of the component is thought to be
more important.
Component parts are expressed as the percentage of the total
Component bar diagram is drawn with all bars having equal
length.
13. This diagrams are used for representing two or more
interrelated data, for facilitating comparison.
14. Year Direct taxes( in crores
of Rs.)
Indirect taxes( in crores of
Rs.)
1972 1200 2300
1975 2250 4100
1978 2500 6300
1981 3500 10000
0
2000
4000
6000
8000
10000
12000
1972 1975 1978 1981
Direct taxes( in
crores of Rs.)
Indirect taxes( in
crores of Rs.)
15. This diagram is usually used to represent net quantities, like
net profit, balance payable, deficit or excess etc.
As the observations may be positive or negative, the basic line
is usually drawn in the middle of the paper horizontally.
Positive values are indicated by bars of proportional length,
drawn above the horizontal line.
Negative values by bars of proportional length drawn below
the horizontal line.
18. From the bar diagram, we can interpret/infer:
When to visit crete
Which is the best month based on temperature
Which is the hottest / coolest month
19. You can see that the temperature in january is 22ºC and then it
rises to 40ºC in may.
You would need to have an idea what these temperatures mean
and can then decide what would be best for you.
You might be decide that temperature above 26ºC would be
too hot for you.
You would then go on holiday in January or February, because
the weather will be pleasant but not too hot.
