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Thought-Process to Discover Knowledge

Welcome to nubtrek.

Books and other education websites provide "matter-of-fact" knowledge. Instead, nubtrek provides a thought-process to discover knowledge.

In each of the topic, the outline of the thought-process, for that topic, is provided for learners and educators.

Read in the blogs more about the unique learning experience at nubtrek.
mathsStatistics and ProbabilityStatistics : Analysis of Data

### Pie Charts

Representation of data using pie-charts is explained in this page.

click on the content to continue..

Consider the number of pens a student carries in a group of 20 students. The raw data is given as :

2, 1, 2, 4, 2
3, 2, 2, 2, 3
3, 2, 2, 3, 2
2, 2, 4, 2, 2

The figure provides the tally and tabular representation of the given raw data.

Considering the number of pens a student carries. The figure provides the bar graph. One wants to know the percent of students bringing 2 pens. Another wants to find if the data value of 3 and 4 are combined, will the result be higher than the data-value of 2? The bar graph does not help in answering such questions. One would end up using the actual data values.

Considering the number of pens a student carries. The figure provides a form of graph that helps to answer questions that compare a data-value to the whole or combining two or more neighboring data values to compare. This is called pie-chart.

This represents the following as segments in circle

•  frequency of 1 is 1, which is represented as a segment of orange color.

•  frequency of 2 is 13, which is represented as a segment of blue color.

•  frequency of 3 is 4, which is represented as a segment of purple color.

•  frequency of 4 is 2, which is represented as a segment of yellow color.

The total is 1+13+4+2 = 20.

The word "pie" means: a circular dish, usually cut in angular segments and served.

familiarize with the terminology
pie

Pie Chart : A representation of data as segments of a circle or a disc.

Consider the data:

•  frequency of 1 is 1

•  frequency of 2 is 13

•  frequency of 3 is 4

•  frequency of 4 is 2

The total is 1+13+4+2 = 20
The circle represents the total 20. In that case, what is the angle in the segment representing 1
= 1 xx 360//20.

Drawing a pie-chart: The total is 1+13+4+2 = 20 which represents whole circle with 360^@ angle.

•  Frequency of 1 is 1, and that would be represented by a segment with angle 1 xx 360//20 =18^@ angle.

•  Frequency of 2 is 13, and that would be represented by a segment with angle 13 xx 360//20 =234^@ angle.

•  Frequency of 3 is 4, and that would be represented by a segment with angle 4 xx 360//20 =72^@ angle.

•  Frequency of 4 is 2, and that would be represented by a segment with angle 2 xx 360//20 =36^@ angle.

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