Monday, June 27, 2011

PIE-CHART FOR STATISTICS O LEVEL/IGCSE







It is a graphic device consisting of a circle divided into sectors or pie-shaped devices whose areas are proportional to the various parts into which the whole quantity is devised Angle = Component part x 360/whole quantity








For example If total number of students from UK were 10 out of 50 we will first divide 10 by 50 then will multiply it by 360 according to the formula mentioned above. In the same way we will calculate each and every thing and using these figures we will draw pie chart shown above.


ADVANTAGES

• It is useful when projections are more important than the numerical values. • It provides a strong visual impact.

DISADVANTAGE

• It can not be drawn quickly as bar chart.

COMPARATIVE PIE CHART

The set of data can be compared by using two different pie charts. The area of the circles is proportional to the total quantities they represent.

The r1 and r2 be,the radius of the circles which represent the total TI and T2 respectively. Then

T1/ T2 = (r1/ r2)2


This formula is applied when two pie chart similar to each other are given then we will apply formula given T1/T2=(r1/r2)2. Information is always given in the question or labelled on the pie chart.


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