MATH 10041 Lecture 4: Chapter 2: Graph Variation
24 Jan 2019
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Chapter 2: Picturing Variation with Graphs
Lecture #1: 1/24/2019
What is a Distribution?
• The most important tool for organizing the variation in data is called the distribution of
the sample
• Three Main Components of a Numerical Distribution
o Shape (what does it look like visually)
o Center (typical value)
o Variability (horizontal spread)
Examining Distribution
• Visualize the Data
o Use a graph that effectively summarizes the data visually
o Using a picture to display the data will help us see patterns
o Graphs for numerical data include:
▪ Dot plots, histograms, stem plots
o Keep in mind:
▪ Using a picture to display the data will help us see patterns
▪ Use visual representations capture different aspects in the data
▪ The picture must:
• Record data values
• Indicate the frequency (count) of the data values
• Summarize the Data
o Shape: is there symmetry?
o Center: is there a most common value?
o Spread: are any data values far from the rest of the data?
Stem and Leaf Plot
Dot Plot
