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Scatterplots and correlation review

A scatterplot is a type of data display that shows the relationship between two numerical variables. Each member of the dataset gets plotted as a point whose x-y coordinates relates to its values for the two variables.

What is a scatterplot?

A scatterplot is a type of data display that shows the relationship between two numerical variables. Each member of the dataset gets plotted as a point whose (x,y) coordinates relates to its values for the two variables.
For example, here is a scatterplot that shows the shoe sizes and quiz scores for students in a class:
Each data point is a student whose x-coordinate gives their shoe size and y-coordinate gives their quiz score.
Want to learn more about constructing scatterplots? Check out this video.

What is correlation?

We often see patterns or relationships in scatterplots.
When the y variable tends to increase as the x variable increases, we say there is a positive correlation between the variables.
Positive correlation
When the y variable tends to decrease as the x variable increases, we say there is a negative correlation between the variables.
Negative correlation
When there is no clear relationship between the two variables, we say there is no correlation between the two variables.
No correlation
Want to learn more about types of correlation? Check out this video.

Practice

problem 1
The graph shown below shows the relationship between the age of drivers and the number of car accidents per 100 drivers in the year 2009.
What is the best description of this relationship?
Choose 1 answer:

Want to practice more problems like these? Check out this exercise on positive and negative correlations.

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