18. Types of Charts: (a) Simple Bar Chart, (b) Multiple Bar Chart, (c) Component Bar Chart, (d) Percentage Component Bar Chart, and (e) Pie Chart. Unit.no. 1

Types of Charts:

(a)    Simple Bar Chart,

(b)   Multiple Bar Chart,

(c)    Component Bar Chart,

(d)   Percentage Component Bar Chart, and

(e)    Pie Chart. 

(a)   Simple Bar Chart:

1.    Simple bar chart consists of vertical or horizontal bars of equal width.

2.    The length of the bars is taken proportionately to the magnitude of the values represented.  The width of the bars has no significance.

3.    Vertical bars are used to represent quantitative data or chronological data.  Whereas, the horizontal bars are represented for qualitative data or geographical data.

4.    If the data do not relate to time, then they should be arranged in ascending or descending order of magnitude.

Exports of Pakistan (in US $ million)

Year	Exports
1948	138
1951	406
1961	378
1971	683
1981	2958
1991	6168
2001	9202
2005	14410

(b)   Multiple Bar Chart:

1.    Multiple bar chart is an extension of simple bar chart.

2.    Grouped bars are used to represent related sets of data. For example, imports and exports of a country together are shown in multiple bar chart.

3.    Each bar in a group is shaded or coloured differently for the sake of distinction.

Years	Imports	Exports
	Rs. (billion)	Rs. (billion)
1982-83	68.15	34.44
1983-84	76.71	37.33
1984-85	89.78	37.98
1985-86	90.95	49.59
1986-87	92.43	63.35
1987-88	111.38	78.44

(c)    Component Bar Chart:

1.      This chart consists of bars which are sub-divided into two or more parts.

2.      The length of the bars is proportional to the totals.

3.      The component bars are shaded or coloured differently.

Current and Development Expenditure – Pakistan (All figures in Rs. Billion)

Years	Current Expenditure	Development Expenditure	Total Expenditure
1988-89	153	48	201
1989-90	166	56	222
1990-91	196	65	261
1991-92	230	91	321
1992-93	272	76	348
1993-94	294	71	365
1994-95	346	82	428

(d)   Percentage Component Bar Chart:

1.    Component bar charts may also be drawn on percentage basis by expressing the components as percentages of their respective totals.

2.    All the bars are of equal length showing the 100%.  These bars are sub-divided into component bars in proportion to the percentages of their components.

Areas Under Crop Production (1985-90)

(‘000 hectors)

Year	Wheat	Rice	Others	Total
1985-86	7403	1863	1926	11192
1986-87	7706	2066	1906	11678
1987-88	7308	1963	1612	10883
1988-89	7730	2042	1966	11738
1989-90	7759	2107	1970	11836

Percentage Areas Under Production

Year	Wheat	Rice	Others	Total
1985-86	66.2%	16.6%	17.2%	100%
1986-87	66.0	17.7	16.3	100
1987-88	67.2	18.0	14.8	100
1988-89	65.9	17.4	16.7	100
1989-90	65.6	17.8	16.6	100

(e)   Pie Chart:

1.    Pie chart is used to compare the relation between the whole and its components.

2.    The difference between the component bar chart and pie chart is that in case of component bar chart the length of the bars are used while in case of a pie chart the area of the sector of a circle is used.

3.    In pie chart, the circle is drawn with radii proportional to the square root of the quantities to be represented because the area of a circle is given by 2pr².

4.    The sectors are coloured and shaded differently.

5.    To construct a pie chart, we draw a circle with some suitable radius (square root of the total).  The angles are calculated for each sector as follows:

Angles for each sector =          Component Part           ×          360^o

                                                   Total