- 109 Views
- Uploaded on

Download Presentation
## PowerPoint Slideshow about ' Correlation' - yoshio-wallace

**An Image/Link below is provided (as is) to download presentation**

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Correlation Coefficient (r)

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.

Correlation (r)

- 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.

Strong Negative

No Correlation

Strong Positive

-1

1

0

Let’s explore….

- www.whfreeman.com/tps4e

Pearson’s Correlation Coefficient

Think about z-scores of the x & y

Pearson’s Correlation Coefficient

Think about z-scores of the x & y

Pearson’s Correlation Coefficient

Think about z-scores of the x & y

AP Exam Tip

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.

Properties of “r”

- 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

Try One!

- Create scatterplot
- Find the correlation
- Describe the association

Homework

- Page 160 (14-18, 21, 26)

Download Presentation

Connecting to Server..