Graphic is a geometric representation of a set of data used to facilitate the understanding of the information presented in this set. Graphs help you quickly identify patterns, check results and compare measures. Furthermore, they can be used in different ways and in different areas of knowledge.
See the elementsbasics for all kinds of graphic and the most used graphics in statistics.
See too: Centrality measures (average, mode and median)
Graphic elements
1. Title: presents in a clear and direct way what the information present in the graph represents and, sometimes, the measurement unit used for this information or some transformation for it;
2. Subtitle: is used to identify the information displayed in the graph, separated by color or by hatching;
3. Sourceinresearch: website, blog, page, research, newspaper, magazine or any other source for building the graphic.
Now see the existing chart types:
Chart Types
bar chart
are made through rectangles to represent the amount relative to each information
. These rectangles are aligned by their base, and their height varies according to the variation in the magnitude they represent. In addition, each bar (rectangle) is related to information, which can be a period, person, etc. See an example:
This graph could also be presented through horizontal bars. Note that the legend is made so that each color represents a school class. The context of the graphic is evident in the title used. This chart has no explicit font because it was created just for this example.
See too:What is 2nd degree function graph?
Do not stop now... There's more after the advertising ;)
line graph
You graphicsinlines show the trajectory of data variation according to the evolution of the quantity that is on the horizontal axis of the graph. By transforming the graph from the previous example into a line graph, we will have:
Note that when the line grows from one year to the next, it means that there has been an increase in the number of students in that grade at that school. The same happens when the line is continuous or when it is decreasing: the number of students remained unchanged or decreased.
Pie charts
You graphicsinsectors are also called pie charts. To build them, just split a circle in circular sectors - which resemble pizza slices - proportionally to each information.
In the previous example, you would need three pie charts, one for each series, as each pie chart corresponds to one of the columns used in the table. Each pie chart can also represent a row in the table, but in the example we're looking at, we've chosen the opposite.
The image below shows only the number of seventh graders from the years 2014 to 2018.
You sectorsof thatgraphic are obtained by rule of three. The number of existing students from 2014 to 2018 is added. This total is equal to the center angle of the entire graph: 360°. Then, just find the center angle relative to the number of students each year and build the sectorCircular within the graph.
By Luiz Paulo Moreira
Graduated in Mathematics
Would you like to reference this text in a school or academic work? Look:
SILVA, Luiz Paulo Moreira. "What is a graphic?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/matematica/o-que-e-grafico.htm. Accessed on June 27, 2021.
