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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

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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 What does the figure depict?

• the figure does not represent the given raw data
• the figure provides the tally and table form of the given raw data
• the figure provides the tally and table form of the given raw data

The answer is "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.

Which of the following is a meaning for the word "pie"?

• a circular dish, usually cut in angular segments and served
• a circular dish, usually cut in angular segments and served
• 3.1415 xx 2.718

The answer is "a circular dish, usually cut in angular segments and served".

What is the term used to refer "a circular dish, usually cut in angular segments and served"?

• Pronunciation : Say the answer once

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
• 1 xx 360//20
• angle is approximately chosen, no calculations required

The answer is "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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