Compound/Cumulative/Divided Bar Graph
Major cash crops exported in Kenya in tonnes
CROP 
1990 
1991 
1992 
1993 
1994 
COFFEE 
4500 
5000 
5200 
6000 
5900 
TEA 
1300 
1100 
2500 
2100 
2200 
MAIZE 
800 
900 
500 
400 
400 
WHEAT 
600 
500 
600 
700 
500 
Steps
CROP 
1990 
CT 
1991 
CT 
1992 
CT 
1993 
CT 
1994 
COFFEE 
4500 
4500 
5000 
5000 
5200 
5200 
6000 
6000 
5900 
TEA 
1300 
5800 
1100 
6100 
2500 
7700 
2100 
8100 
2200 
MAIZE 
800 
6600 
900 
7000 
500 
8200 
400 
8500 
400 
WHEAT 
600 
7200 
500 
7500 
600 
8800 
700 
9200 
500 
TOTAL 
7200 
7500 
8800 
9200 
9000 
 Set cumulative totals for the data each year
 Draw vertical axis(Y) to represent dependent variable
 Draw horizontal axis(x) to represent independent variable
 Label both axis using suitable scale
 Plot the cumulative values for each year
 Use values for components to subdivide the cumulative bar
 The subdivisions are placed in descending order with the longest at the bottom(coffee)
 Shade each component differently
 Put title and key
Advantages
 It’s easy to construct
 It has good visual impression
 There is easy comparison for the same component in different bars because of uniform shading
 Easy to interpret because bars are shaded differently
 Total value of the bar can be identified easily
Disadvantages
 It doesn’t show the trend of components (change over time).
 Can’t be used to show many components as there is limited space upwards
 Tedious as there is a lot of calculation work involved.
 Not easy to trace individual contribution made by members of the same bar
 Poor choice of vertical scale causes exaggeration of bars length leading to wrong conclusions
Analysis
 Coffee was the leading export earner in the five years.
 Tea was the second leading export earner.
 Wheat had the lowest export quantity.
 1993 recorded the highest export quantity.
 1990 recorded the lowest export quantity.
Piechart/Divided Circles/Circle Charts
 A circle which has been subdivided into degrees used to represent statistical data where component values have been converted in degrees.
Major countries producing commercial vehicles in the world in 000s
USA 
FRANCE 
JAPAN 
UK 
GERMANY 
RUSSIA 
1800 
240 
2050 
400 
240 
750 
Steps
 Convert components into degrees
USA ^{1800}/_{5480}×360=118.2◦
FRANCE ^{240}/_{5480}×360=15.8◦
JAPAN ^{2050}/_{5480}×360=134.7◦
UK ^{400}/_{5480}×360=26.3◦
GERMANY ^{240}/_{5480}×360=15.8◦
RUSSIA ^{750}/_{5480}×360=49.3◦  Draw a circle of convenient size using a pair of compasses.
 From the centre of the circle mark out each calculated angle using a protractor.
 Shade the sectors differently and provide the key for various shadings.
Advantages
 Gives a good/clear visual impression
 Easy to draw.
 Can be used to present varying types of data e.g. minerals, population, etc.
 Easy to read and interpret as segments are arranged in descending order and are also well shaded.
 Easy to compare individual segments.
Disadvantages
 Difficult to interpret if segments are many.
 Tedious due to a lot of mathematical calculations and marking out of angles involved.
 Can’t be used to show trend/change over a certain period.
 Small quantities or decimals may not be easily represented.
Analysis
 The main producer of commercial vehicles is Japan.
 The second largest producer is USA followed by Russia.
 The lowest producers were France and West Germany with.
Proportional Circles
 This is use of circles of various sizes to represent different sets of statistical data.
Table showing mineral production In Kenya from year 19982000
MINERALS 
QUANTITY IN TONNES 

1998 
1999 
2000 

Graphite 
200 
490 
930 
Fluorspar 
30 
255 
450 
Soda ash 
270 
300 
350 
Diamond 
500 
870 
1270 
TOTAL 
1000 
1915 
3000 
Steps
 Determining the radii of circles by finding the square roots of the totals
1998 √1000=31.62=32
1999 √1915=43.76=44
2000 √3000=54.77=55
 Scale:1cm represents 10 tonnes
1998=3.2 cm
1999=4.4 cm
2000=5.5 cm
 Using a pair of compasses draw circles of different radii representing mineral production in Kenya between 1998 and 2000.
 Convert component values into degrees
Component value/total value of data×360
1998: Graphite200/1000×360=72◦
Fluorspar30/1000×360=10.8◦
Soda ash270/1000×360=97.2◦
Diamond500/1000×360=180◦
1999: Graphite490/1915×360=92.1◦
Fluorspar255/1915×360=47.9◦
Soda ash`300/1915×360=56.4◦
Diamond870/1915×360=163.6◦
2000: Graphite930/3000×360=11.6◦
Fluorspar450/3000×360=54◦
Soda ash350/3000×360=42.1◦
Diamond1270/3000×360=152.3◦
 On the proportional circle for each year use a protractor and mark out the angles
 Shade the segments and then provide a key.
Advantages
 They give a good visual impression.
 Easy to compare various components.
 Simple to construct.
 Easy to interpret as segments are arranged in descending order.
 Can be used to present varying types of data.
Disadvantages
 Tedious in calculation and measurement of angles
 Actual values represented by each component cant be known at a glance
 Difficult to accurately measure and draw sectors whose values are too small.
 Comparison can be difficult if the circles represent values which are almost equal.
Analysis/Conclusions
 Diamond was leading in production.
 The second leading mineral in production was graphite.
 The mineral with the lowest production was fluorspar.
Download Statistics  Geography Form 3 Notes.
Tap Here to Download for 50/
Get on WhatsApp for 50/
Join our whatsapp group for latest updates