logging in or signing up Unit 2 Lesson 2 Stacey94 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 143 Category: Entertainment License: All Rights Reserved Like it (0) Dislike it (0) Added: June 14, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: gfrr (15 month(s) ago) can i download please Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: Unit 2: Bivariate Relationships Lesson 2: Covariance and Pearson r EDER 6010: Statistics for Educational Research Dr. J. Kyle Roberts University of North Texas Next Slide Covariance : Are The Variables Correlated??? Covariance “The average cross-product of the deviation scores.” Answers 2 Questions: 1. Is there any relationship between X and Y? 2. If there is a relationship, is it positive or negative? Next Slide “Rules” for Covariance : “Rules” for Covariance Covariance will be 0 (zero) when the sum of the cross- products is 0 (e.g., IQ and shoe size) The “sign” of the covariance tells the “direction” of the relationship Do they “Covary” Together??? 1. There are no “bounds” for values for the covariance Are The Variables Correlated??? Next Slide Pearson r : Pearson r “The average cross-product of the standardized deviation scores.” Answers 3 Questions: 1. Is there any relationship between X and Y? 2. If there is a relationship, is it positive or negative? 3. How well does one line describe the data? Next Slide Pearson r : Pearson r “How well does a single line represent my data?” r = .85 r = -.25 r = 1.0 Next Slide Pearson r : Pearson r r = .00 Next Slide “Guessing” Pearson r : “Guessing” Pearson r Height and weight Moderate Positive SES and Math Achievement High Negative Tobacco use and Life Expectancy High Positive GPA and SAT Near Zero Shoe size and IQ Moderate to High Positive Next Slide “Rules” for Pearson r : “Rules” for Pearson r A zero value for the Pearson r means that there is NO relationship between the two variables of interest Pearson r’s cannot be compared between two studies 1. The “bounds” for Pearson r are between +1.0 and -1.0 4. The Covariance determines the sign of the Pearson r Next Slide Square Before You Compare : Square Before You Compare R2 = .25 R2 = .36 “Study 2 explains 11% more variance than Study 1” Next Slide A Little Practice : A Little Practice r = 1.0 r = .832 Next Slide Slide 11: Unit 2: Bivariate Relationships Lesson 2: Covariance and Pearson r EDER 6010: Statistics for Educational Research Dr. J. Kyle Roberts University of North Texas You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
Unit 2 Lesson 2 Stacey94 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 143 Category: Entertainment License: All Rights Reserved Like it (0) Dislike it (0) Added: June 14, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: gfrr (15 month(s) ago) can i download please Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: Unit 2: Bivariate Relationships Lesson 2: Covariance and Pearson r EDER 6010: Statistics for Educational Research Dr. J. Kyle Roberts University of North Texas Next Slide Covariance : Are The Variables Correlated??? Covariance “The average cross-product of the deviation scores.” Answers 2 Questions: 1. Is there any relationship between X and Y? 2. If there is a relationship, is it positive or negative? Next Slide “Rules” for Covariance : “Rules” for Covariance Covariance will be 0 (zero) when the sum of the cross- products is 0 (e.g., IQ and shoe size) The “sign” of the covariance tells the “direction” of the relationship Do they “Covary” Together??? 1. There are no “bounds” for values for the covariance Are The Variables Correlated??? Next Slide Pearson r : Pearson r “The average cross-product of the standardized deviation scores.” Answers 3 Questions: 1. Is there any relationship between X and Y? 2. If there is a relationship, is it positive or negative? 3. How well does one line describe the data? Next Slide Pearson r : Pearson r “How well does a single line represent my data?” r = .85 r = -.25 r = 1.0 Next Slide Pearson r : Pearson r r = .00 Next Slide “Guessing” Pearson r : “Guessing” Pearson r Height and weight Moderate Positive SES and Math Achievement High Negative Tobacco use and Life Expectancy High Positive GPA and SAT Near Zero Shoe size and IQ Moderate to High Positive Next Slide “Rules” for Pearson r : “Rules” for Pearson r A zero value for the Pearson r means that there is NO relationship between the two variables of interest Pearson r’s cannot be compared between two studies 1. The “bounds” for Pearson r are between +1.0 and -1.0 4. The Covariance determines the sign of the Pearson r Next Slide Square Before You Compare : Square Before You Compare R2 = .25 R2 = .36 “Study 2 explains 11% more variance than Study 1” Next Slide A Little Practice : A Little Practice r = 1.0 r = .832 Next Slide Slide 11: Unit 2: Bivariate Relationships Lesson 2: Covariance and Pearson r EDER 6010: Statistics for Educational Research Dr. J. Kyle Roberts University of North Texas