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Displaying and Describing Categorical Data - Coggle Diagram
Displaying and Describing Categorical Data
The Three Rules of Data Analysis
Make a picture. A display of your data will reveal things you are not likely to see in a table of numbers and will help you to Think clearly about the patterns and relation-ships that may be hiding in your data.
Make a picture. A well-designed display will Show the important features and patterns in your data. A picture will also show you the things you did not expect to see.
Make a picture. The best way to Tell others about your data is with a well-chosen picture.
It's important to analyze data in order to understand it.
The Area Principal
The area principle says that the area occupied by a part of the graph should correspond to the magnitude of the value it repre-sents.
Violations of the area principle are a common way to lie with Statistics
Frequency Tables: Making Piles
A relative frequency table shows the percentages, rather than the counts, of the values in each category. The percentages shown are from specific situations and scenarios.
In order to know the fraction or proportion of the data in each category, divide the counts by the total number of cases. Usually we multiply by 100 to express these proportions as percentages.
They de-scribe the distribution of a categorical variable because they name the possible categories and tell how frequently each occurs.
Bar Charts
A bar chart shows the distribution of a categorical variable, showing the counts for each category next to each other for easy comparison.
The bars are the same width, so their heights determine their areas, and the areas are proportional to the counts
The bars are lined up along a common base
Bar charts should have small spaces between the bars to indicate that these are freestanding bars that could be rearranged into any order.
Pie Charts
Pie Charts show the group of cases in a circle. They slice the circle into pieces whose sizes are proportional to the fraction of the whole in each category.
Pie charts give the impression of how a whole group is partitioned into smaller groups.
Contingency Tables
Shows how individuals are distributed along each variable. Each cells gives you the count for the combination of values for the two variables.
In a contingency table, when the distribution of one variable is the same for all categories of another, we say that the variables are independent. Which means there is no connection between variables
Conditional Distributions
Show the distribution of one variable for just those cases that satisfy a condition on another variable.
Segmented Bar chart
The whole set of data is represented in a single bar, but is divided by percentages, according to how much they represent.