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Course: Statistics — Third Secondary
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Text lesson

Correlation

Statistics — Third Secondary

Correlation

The idea of correlation and the scatter diagram

The idea of correlation and the scatter diagram

  • Correlation is the relationship between two variables we study how a change in one variable goes with a change in the other. Examples include the number of hours a student studies and the student’s exam score, or the temperature and the number of cold drinks sold.
  • The relationship between two variables is shown by a scatter diagram.
  • Each pair of values (x, y) is plotted as a point on the coordinate plane.
  • The direction of the points tells us the type of relationship:
Key points
Positive correlationas x increases, y generally increases. The points rise from the lower left to the upper right.
Negative correlationas x increases, y generally decreases. The points fall from the upper left to the lower right.
No correlationthe points are scattered with no clear direction.
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