L6 - Simple Linear Regression.pptx

L6 - Simple Linear Regression.pptx - Lecture 6 Linear...

This preview shows page 1 - 11 out of 40 pages.

Lecture 6 Linear Regression and Correlation Analysis Chapter 14, Groebner 1
Image of page 1

Subscribe to view the full document.

Chapter Goals After completing this chapter, you should be able to: I. Calculate and interpret the simple correlation between two variables II. Calculate and interpret the intercept and gradient of a simple linear regression equation for a set of data III. Calculate coefficient of determination, R 2 and indicate if it’s a good fit data. 2
Image of page 2
Scatter Plots and Correlation A scatter plot (or scatter diagram) is used to show the relationship between two variables Correlation analysis is used to measure strength of the association (linear relationship) between two variables Only concerned with strength of the relationship 3
Image of page 3

Subscribe to view the full document.

Scatter Plot Examples y y x y y x Linear relationships Curvilinear relationships x 4
Image of page 4
Scatter Plot Examples y y x y y x Strong relationships Weak relationships (continued) x x 5
Image of page 5

Subscribe to view the full document.

Scatter Plot Examples y x y x No relationship (continued) 6
Image of page 6
Correlation Coefficient, r Correlation measures the strength of the linear association between two variables The sample correlation coefficient, r is a measure of the strength of the linear relationship between two variables, based on sample observations (continued) 7
Image of page 7

Subscribe to view the full document.

Features of r Unit free Range between -1 and 1 The closer to -1, the stronger the negative linear relationship The closer to 1, the stronger the positive linear relationship If r > |0.5|, indicates strong relationship The closer to 0, the weaker the linear relationship 8
Image of page 8
The Coefficient of Correlation, r 9 -1 -0.7 -0.3 0 0.3 0.7 1.0 Weak positive Weak negative Strong negative Moderate negative Strong positive Moderate positive
Image of page 9

Subscribe to view the full document.

r = +.3 r = +1 Examples of Approximate r Values y x y x y x y x y x r = -1 r = -.6 r = 0 10
Image of page 10
Image of page 11

{[ snackBarMessage ]}

Get FREE access by uploading your study materials

Upload your study materials now and get free access to over 25 million documents.

Upload now for FREE access Or pay now for instant access
Christopher Reinemann
"Before using Course Hero my grade was at 78%. By the end of the semester my grade was at 90%. I could not have done it without all the class material I found."
— Christopher R., University of Rhode Island '15, Course Hero Intern

Ask a question for free

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