R Lang

• Random Variable


  A rule that assigns a numerical value to each outcome in a sample space
• Types of Random Variable

  • Discrete
  • Continuous
• Discrete Random Variable


  Can take only a finite number of distinct values such as 0,1,2,3,4, 5,… and so on. It is a variable whose value is obtained by counting.
• Continuous Random Variable


  The set of its possible values is uncountable; It is a variable whose value is obtained by measuring.
• Plotting Single Continuous Random Variable

  • Histogram
  • Density Plot
  • Box-Whisker Plot
• Use the syntax "str()" to check the structure of the dataset
• Histogram


  A graphical display of data using bars of different heights. It is similar to a Bar Chart, but a histogram groups numbers into ranges. Histograms are a great way to show results of continuous data.
• When the data is in categories (such as Ranks or Sections), we should use a Bar Chart instead of a Histogram
• Creating a Histogram

  1. hist()

  2. Add x-axis label

  3. Add y-axis label

  4. Add title

  5. Adjust number of bins
• Density Plot


  Visualizes the distribution of data over a continuous interval or time period. This chart is a variation of a Histogram. An advantage Density Plots have over Histograms is that they're better at determining the distribution shape.
• Creating a Density Plot

  plot(density(variable))
• Box Plot (Box and Whisker Plot)

  Displays the five-number summary of a set of data: minimum, first quartile, median, third quartile, and maximum.
• Creating a Box Plot

  1. boxplot(variable)

  2. Make it horizontal
• Range


  The distance between the smallest (minimum) and the largest (maximum) data points
• Interquartile Range (IQR)


  The distance between the first quartile (Q1 = 25%) and the third quartile (Q3 - 75%) in the data
• Bar Graph


  Plots numeric values for levels of a categorical feature as bars. Levels are plotted on one chart axis, and values are plotted on the other axis.
• Bar Graphs are good when your data is in categories
• Horizontal bar graphs are best for nominal variables, vertical bar graphs are best for ordinal variables
• Bar graphs are used to measure the changes over a period of time
• Creating a Bar Graph

  1. table(variable)

  2. plot(table(variable))

  3. barplot(table(variable))
• Scatterplot


  A graph of plotted points that show the relationship between two sets of data. The scatter diagram graphs pairs of numerical data, with one variable on each axis, to look for a relationship between them.
• Scatterplots are used when we have paired numerical data, when there are multiple values of the dependent variable for a unique value of an independent variable, and in determining the relationship between variables
• Types of Correlation in Scatterplots

  • Positive Correlation
  • Negative Correlation
  • No Correlation
• Creating a Scatterplot


  1. plot(x, y)

  2. Add axis labels and title

  3. Add jitter

  4. Add abline (horizontal, vertical, trendline)

  5. Change plot character
• Pie Chart


  A type of graph that represents the data in a circular graph. The slices of pie show the relative size of the data, and it is a type of pictorial representation of data. A pie chart requires a list of categorical variables and numerical variables.

  
• Pie charts are ideal for categorical data groups since every single slice can show a specific category

  
• Pie charts are best for showing percentages of a whole, while bar graphs are better for comparing different categories of data or tracking changes over time

  
• Creating a Pie Chart

  1. pie(values)

  2. Add labels and title

  
• Syntax for Histogram is hist().
• Syntax for Density Plot is plot().
• Syntax for Box Plot is boxplot().
• Give me a sample syntax creating more bins to the histogram.

  hist(chickwts$weight, xlab="Weight", ylab= "Frequency", main="Chicken Weights", breaks = 16)
• Give me a sample syntax creating specific bins to the histogram

  hist(chickwts$weight, xlab="Weight", ylab= "Frequency", main="Chicken Weights", breaks = 100, 200, 300, 400, 500)
• Give me a sample syntax adding labels on the histogram

  hist(chickwts$weight, xlab="Weight", ylab= "Frequency", main="Chicken Weights", labels = T)
• Give me a sample syntax adding colors on the histogram

  hist(chickwts$weight, xlab="Weight", ylab= "Frequency", main="Chicken Weights", labels = T, col = c(“Red”, “Green”, “Blue”))