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Dot Plots

Site: Clare-Gladwin RESD
Course: Michigan Algebra II KHauck
Book: Dot Plots
Printed by: Guest user
Date: Tuesday, November 26, 2024, 12:49 AM

Description

Dot Plots

Table of contents

Dot Plots

A few of the methods to display data are dot plots, bar graphs, histograms, and box plots. A display of data allows us to see patterns, predict outcomes, and gives an overview of the data.

A dot plot is a statistical chart consisting of a group of data points plotted on a simple scale. To interpret a dot plot:
  • Each dot can represent a single observation from a set of data, or a specified number of observations from a set of data.
  • The dots are stacked in a column over a category, so that the height of the column represents the relative or absolute frequency of observations in the category.
  • The pattern of data in a dot plot can be described in terms of symmetry and skewness only if the variable is not categorical.

Example

Suppose 30 first graders are asked to pick their favorite color. Their choices can be summarized in a dot plot, as shown below.

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Red

Orange

Yellow

Green

Blue

Indigo

Violet

Each dot represents one student, and the number of dots in a column represents the number of first graders who selected the color associated with that column. For example, Red was the most popular color (selected by 9 students), followed by Blue (selected by 7 students). Selected by only 1 student, Indigo was the least popular color.

In this example, note that the category (color) is a categorical variable, so it is not appropriate to talk about the symmetry or skewness of this dot plot.


Practice

Dot Plot Worksheet

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Answer Key

Answer Key for Dot Plots Worksheet

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Sources

Sources used in this book:

"Dot Plot." http://stattrek.com/AP-Statistics-1/Dotplot.aspx (accessed 7/26/2010).

Embracing Mathematics, Assessment & Technology in High Schools; a Michigan Mathematics & Science Partnership Grant Project

Wikipedia, "Dot Plot (Statistics)." http://en.wikipedia.org/wiki/Dot_plot_(statistics) (accessed 7/26/2010).