4.1 tables and graphs for the relationship between two variables objectives: by the end of this...
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4.1 Tables and Graphs for the Relationship Between TwoVariablesObjectives:By the end of this section, I will beable to…
1) Construct and interpret crosstabulations for two categorical variables.
2) Construct and interpret clustered bar graphs for two categorical variables.
3) Construct and interpret scatterplots for two quantitative variables.
Section 4.1Tables and Graphs for
TWO Variables.
Crosstabulation
• Fancy word for a table. It is also known as a two-way table
• Helps you look for patterns in a data set.
Two-way Table
• Make a two way table to help you organize information.
Who? Who? TOTAL
What?
What?
TOTAL
Question: Do you eat breakfast regularly?
Two-way Table
Male Female TOTAL
Eats Breakfast Regularly
Doesn’t Eat Breakfast RegularlyTOTAL
Question: Do you eat breakfast regularly?
Graphs for Crosstabulations
When to use?
• Crosstabulations and clustered bar graphs are useful for summarizing the relationship between CATEGORICAL variables.
What happens if you have QUANTITATIVE data?
• Use a SCATTERPLOT
SCATTER PLOTS• graphs that display a relationship
between two variables
VARIABLES
What are the two variables?
What are the two variables?
Three Types of Scatterplot Relationships
• Positive• Negative• No relationship
ASSOCIATIONPositive Relationship:
Larger values of one variable tend to be associated with larger values of the other variable.
Negative Relationship:Larger values of one
variable tend to be associated with smaller values of the other variable.
NO RELATIONSHIP
EXAMPLES
Question?
• Is there a relationship between how many digits you can type into your calculator and how fast you can do it?
Total Digits Typed
Tim
e (i
n s
eco
nd
s)
x axis
y ax
is