2.15:

2.15: Diagramme circulaire

JoVE Core
Statistics

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JoVE Core Statistics

Pie Chart

2.14: Pareto Chart

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01:04 min

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April 30, 2023

Overview

A pie chart (or a pie graph) is a circular graphical chart or a pictorial representation of categorical data. It is divided into slices of pie each indicating numerical proportions. It is also used to show the relative sizes of data in a single chart.

In a pie chart, the central angle, the arc length of each slice, and the area are directly proportional to the quantity or percentage it represents. Some real-world examples that can be depicted using pie charts include marks obtained by students in a class, the monthly expenditure of a family, and the cost of construction of a house. With the help of a pie chart, one can easily compare the sum spent on steel, cement, and so on during construction. The actual sum spent on each individual expense can also be computed.

A pie chart's main advantages are that it is simple to use and easy for the audience to quickly analyze and understand information. However, if there is a lot of data, it may become challenging for readers to visualize and assimilate information using a pie chart.

Transcript

Prenons l’exemple d’un tableau qui résume l’occurrence des cas de COVID-19 dans différents pays. De telles données qualitatives avec les comptages de fréquence peuvent être représentées à l’aide du graphique circulaire, un graphique en forme de cercle, tout comme un camembert.

Alors, comment les données d’un tableau sont-elles converties en graphique circulaire ?

Tout d’abord, divisez le nombre de cas de COVID dans le pays A par la somme de tous les cas de COVID. Multipliez cette valeur par 360 degrés (les degrés d’un cercle complet) pour obtenir l’angle sectoriel du pays correspondant.

De même, calculez les angles sectoriels pour les autres pays. À l’aide de ces angles de secteur, divisez le cercle en tranches équivalentes au nombre donné de catégories.

Notez que le pourcentage de fréquences des cas de COVID correspond également à la taille de leurs tranches. Ici, le pays E, avec le secteur le plus important, indique le pourcentage le plus élevé de cas de COVID. En revanche, le pays F, avec le plus petit angle sectoriel, affiche le pourcentage le plus faible de cas.

Key Terms and definitions

Pie Chart - A circular graphical representation of categorical data and proportions.
Sectors - The individual slices of a pie chart representing specific data.
Central Angle - In pie chart, an angle proportional to the represented data.
Categorical Data - Information that can be categorised into groups; often represented by pie charts.
Relative Frequency - The proportion of the total data value that an individual category represents.

Learning Objectives

Define Pie Chart – Understand its role in data visualization (e.g., pie chart).
Contrast Piechart and Bar Graph– Highlight key differences (e.g., categorical vs quantative data).
Explore Pie Chart Examples – Understand its usage in real-life scenarios (e.g., family expenses).
Explain Central Angle - Its connection to the data portion in a pie chart.
Apply Pie Charts in Context – Methodology for creating pie charts using raw data.

Questions that this video will help you answer

What is a pie chart and how does it represent categorical data?
How is central angle used in the construction of pie charts?
What are the advantages of using pie charts in data visualization?

This video is also useful for

Students – It assists in understanding data analysis and interpretation using pie charts.
Educators – Provides a comprehensive understanding of pie charts for teaching data visualization.
Researchers – Pie charts are vital for representing categorical data in research.
Statistics Enthusiasts – Offers a deeper understanding of data representation and analysis.

Tags

Graphique circulaire graphique circulaire données catégorielles proportions tailles relatives angle central longueur de l’arc surface dépenses coûts de construction visualisation des données analyse de l’information