{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Chapter 4 (Sp11) - Section 4.1 Scatter Diagrams and...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Section 4.1 – Scatter Diagrams and Correlation Correlation – There is a correlation between two variables when one of them is related to the other in some way. The response variable is the variable whose value can be explained by the value of the predictor (explanatory) variable . Scatter Diagram – A graph in which the (biviariate) paired ( x , y ) sample data are plotted as single points. Each individual in the data set is represented by a single point. The explanatory variable is plotted on the horizontal axis and the response variable is plotted on the vertical axis. Example : Create a scatterplot of the following data: Looking at a scatter diagram can help you determine if the variables have a linear relationship. (See the graphs on pg. 194) The linear correlation coefficient ( r ) measures the strength and direction of the linear relationship between the two variables. It is also called the Pearson product moment correlation coefficient. - - - = 2 2 2 2 ) ( ) ( ) ( ) ( ) )( ( y y n x x n y x xy n r ( ALWAYS ROUND TO 3 DECIMAL PLACES ) x y 3 3 4 2 3 4 1 5 5 2 2 5 5 1 1
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Properties of r : 1. –1 ≤ r ≤ 1 2. The closer r is to +1, the stronger is the evidence of positive association. 3. The closer r is to –1, the stronger is the evidence of negative association.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern