# Quantitative assessment of the strength of the relationship between x & y. It is the measure of the extent to which x & y are linearly related. *It is.

## Presentation on theme: "Quantitative assessment of the strength of the relationship between x & y. It is the measure of the extent to which x & y are linearly related. *It is."— Presentation transcript:

Quantitative assessment of the strength of the relationship between x & y. It is the measure of the extent to which x & y are linearly related. *It is strong if the points lie close to a straight lint and is weak if they are widely scattered about a line.

 It’s a number between -1 and 1.  The closer it is to the ends, the stronger the positive or negative relationship.  It gives the strength and direction. 0 1 Strong Positive No Correlation Strong Negative

 www.whfreeman.com/tps4e www.whfreeman.com/tps4e

Think about z-scores of the x & y

xy 65 103 147 198 2112

xy 15219 27189 31195 42173 88121 92138 66152 51140

If you are asked to interpret a correlation start by looking at a scatterplot of the data. Then be sure to address direction, form, strength, and outliers and put your answer in context.

 It does not depend on the unit of measurement.  It doesn’t depend upon which of the 2 variables is “x”  It’s between -1 and 1  It equals -1 or 1 if all points lie on a straight line  It is strongly affected by a few outliers

Scatterplots show relationships – not cause and effect.

 Create scatterplot  Find the correlation  Describe the association Fat (g)Sodium 29920 311150 341200 351095 391180 391120 431260

 Page 160 (14-18, 21, 26)

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