Bar Charts and Pie Charts in R | R Tutorial 2.1 | MarinStatsLectures

MarinStatsLectures-R Programming & Statistics
9 Aug 201304:51
EducationalLearning
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TLDRIn this educational video, Mike Marin demonstrates how to create bar and pie charts in R using the lung capacity dataset. He explains the use of the 'barplot' and 'table' commands to visualize the categorical variable distribution, including how to display frequencies and percentages. Marin also covers adding titles, labels, and customization options like horizontal bars and rotating axis labels. The video concludes with a guide on generating pie charts and offers tips on further customization.

Takeaways
  • 📊 The video is a tutorial on creating bar and pie charts in R, focusing on summarizing the distribution of categorical variables.
  • 🗂️ The 'barplot' command in R is used to produce bar charts, which can show the frequency or relative frequency of each category.
  • 🔍 The 'table' command in R generates a frequency table for a categorical variable, such as Gender in the provided dataset.
  • 📈 The frequency table can be stored in an object for later use, as demonstrated with the 'count' object.
  • 📊 Relative frequencies or percentages can be calculated by dividing the counts by the total number of observations.
  • 📈 The 'percent' object stores the relative frequencies for later use in creating bar charts.
  • 🎨 The 'barplot' command can be customized with titles, axis labels, and bar labels using various arguments like 'main', 'xlab', 'ylab', and 'names.arg'.
  • 🔄 To display the bar chart horizontally, the 'horiz' argument can be set to TRUE, and axis labels need to be adjusted accordingly.
  • 🌈 The 'pie' command in R is used to produce pie charts, which can also be customized with titles and other visual elements.
  • 🖌️ Customizing the appearance of charts, including colors, can be done by exploring the Help menu in R.
  • 🔎 The video encourages viewers to explore the Help menu in R for more advanced chart customization options.
Q & A

  • What are the two types of charts discussed in Mike Marin's video?

    -The two types of charts discussed are bar charts and pie charts.

  • What is the purpose of bar charts and pie charts in data visualization?

    -Bar charts and pie charts are used for summarizing the distribution of a categorical variable.

  • Which dataset is used in the video for demonstrating the creation of charts?

    -The lung capacity dataset is used for demonstrating the creation of charts in the video.

  • How can one access help in R for a specific command?

    -Help can be accessed by typing 'help' followed by the command name in brackets, or by using a question mark '?' before the command name.

  • What command in R is used to create a frequency table for a categorical variable?

    -The 'table' command in R is used to create a frequency table for a categorical variable.

  • How many females and males are in the sample according to the frequency table created in the video?

    -There are 358 females and 367 males in the sample according to the frequency table.

  • What is the purpose of storing the frequency table in an object called 'count'?

    -Storing the frequency table in an object called 'count' allows for easy access and manipulation of the data for later use in the bar chart.

  • How can the bar chart be expressed using relative frequencies or percentages?

    -The bar chart can be expressed using relative frequencies or percentages by dividing the frequency table by the total number of observations.

  • What command in R is used to create a bar chart?

    -The 'barplot' command in R is used to create a bar chart.

  • How can the bars in a bar chart be made to appear horizontally?

    -The bars in a bar chart can be made to appear horizontally by using the 'horiz' argument and setting it to TRUE.

  • What command in R is used to create a pie chart?

    -The 'pie' command in R is used to create a pie chart.

  • How can the appearance of a pie chart be customized, such as changing colors?

    -The appearance of a pie chart, including colors, can be customized by exploring the Help menu in R for additional options and arguments.

Outlines
00:00
📊 Introduction to Bar and Pie Charts in R

In this video, Mike Marin introduces the process of creating bar and pie charts in R, using the 'barplot' and 'pie' commands. He starts by discussing the purpose of these charts for summarizing categorical variable distributions. The example dataset used is the lung capacity data, which has already been imported and attached in R. The video provides a step-by-step guide on how to produce a bar chart, including accessing help, calculating frequency tables with the 'table' command, and creating bar plots with 'barplot'. It also covers how to display data as percentages and relative frequencies, and how to customize the plot with titles, labels, and horizontal orientation.

Mindmap
Keywords
💡Bar Chart
A bar chart is a graphical representation of data using rectangular bars to show comparisons among categories. In the video's context, it's used to visualize the distribution of a categorical variable, such as the frequency of different genders in a dataset. The script mentions producing a bar chart using the 'barplot' command in R, which is a statistical software, to display the frequency or relative frequency of each category.
💡Pie Chart
A pie chart is a circular chart divided into sectors, illustrating numerical proportion. Each sector's size represents the proportion of the part to the whole. In the video, the 'pie' command in R is used to create a pie chart, which is suitable for summarizing the distribution of a categorical variable by showing the percentage each category contributes to the total.
💡Categorical Variable
A categorical variable is a type of data that can be grouped into categories. It is distinct from numerical variables, which can take on a range of values. In the video, the categorical variable discussed is 'Gender', which is divided into 'female' and 'male' categories, and its distribution is visualized through charts.
💡Frequency
Frequency refers to the number of times an event occurs or a value appears in a dataset. The script explains how to create a frequency table for the 'Gender' variable using the 'table' command in R, which shows the count of females and males in the sample.
💡Relative Frequency
Relative frequency is the proportion of the total number of observations that fall into a particular category. In the video, after calculating the frequency table, the script shows how to convert these frequencies into percentages to get the relative frequency of each gender in the dataset.
💡Percentage
A percentage is a way to express a proportion as a fraction of 100. It is used in the script to represent the relative frequency of each gender category in the dataset. The script demonstrates how to calculate the percentage of females and males and how to use these percentages in a bar chart.
💡Barplot Command
The 'barplot' command in R is used to create bar charts. The script explains how to use this command to visualize the frequency or relative frequency of categories in a dataset. It is a key part of the video's demonstration on producing bar charts.
💡Help Menu
The Help menu in R provides assistance and documentation on commands and functions within the software. The script mentions accessing the Help menu for the 'barplot' and 'pie' commands to get more information on how to use them, which is essential for understanding and customizing the charts.
💡Table Command
The 'table' command in R is used to create a frequency table for a categorical variable. In the video, this command is used to generate a table that shows the count of females and males, which is then used to create a bar chart.
💡Main Argument
In the context of R's plotting functions, the 'main' argument is used to add a title to the plot. The script describes how to use the 'main' argument in the 'plot' command to title the bar and pie charts, which helps in understanding the purpose of the chart.
💡Xlab and Ylab Arguments
The 'xlab' and 'ylab' arguments in R's plotting functions are used to label the x-axis and y-axis of a chart, respectively. The script explains how to use these arguments to label the axes of the bar chart, which is crucial for interpreting the data visualization correctly.
💡Las Argument
The 'las' argument in R's plotting functions is used to control the style of axis labels. In the script, it is set to 1 to rotate the labels on the y-axis, making them more readable, especially when the chart is displayed horizontally.
💡Names.arg Argument
The 'names.arg' argument in R's 'barplot' function is used to specify the labels that appear under each bar in the bar chart. The script uses this argument to label the bars as 'female' and 'male', which corresponds to the categories of the 'Gender' variable.
💡Horiz Argument
The 'horiz' argument in R's 'barplot' function is used to determine the orientation of the bar chart. When set to TRUE, it makes the bars appear horizontally instead of vertically. The script explains how to use this argument to change the orientation of the bar chart for better visualization.
Highlights

Introduction to producing bar charts and pie charts in R for summarizing categorical variable distributions.

Use of lung capacity data set for demonstration purposes.

Explanation of the 'barplot' command in R for creating bar charts.

Accessing the Help menu in R for command assistance.

Understanding bar charts as visual displays of frequency or relative frequency.

Generating a frequency table using the 'table' command in R.

Storing the frequency table in an object for later use.

Calculating relative frequencies or percentages for the bar plot.

Storing calculated percentages in an object for later reference.

Producing a bar chart with 'barplot' using counts or frequencies.

Creating a bar chart with relative frequencies or percentages.

Adding titles and axis labels to the bar chart using 'main', 'xlab', and 'ylab' arguments.

Rotating y-axis labels for better readability with the 'las' argument.

Customizing bar labels using the 'names.arg' argument.

Creating horizontal bar charts with the 'horiz' argument set to TRUE.

Adjusting axis labels for horizontal bar charts.

Exploring the Help menu in R for customizing plot colors and other features.

Producing pie charts using the 'pie' command in R.

Adding a title to the pie chart and customizing with the 'box' command.

Encouragement to explore the Help menu for further customization options.

Closing remarks and invitation to watch other instructional videos.

Transcripts

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Related Tags
Data VisualizationR ProgrammingBar ChartsPie ChartsCategorical DataLung CapacityFrequency AnalysisPercentagesRelative FrequenciesGraphical RepresentationStatistical Analysis