Lecture Communication research: Asking questions, finding answers (2/e): Chapter 12 - Joann Keyton

Chapter 12 Testing for Relationships Tests of linear relationships – Correlation 2 continuous level variables – Regression 2 or more continuous level variables Identifies statistically significant linear patterns in the association of variables 1 © 2006 by The McGraw­Hill Companies, Inc. All rights reserved. Basic Assumptions Data collected from sample to draw conclusion about population Data from normally distributed population Appropriate variables are selected to be tested using theoretical models Participants randomly selected 2 © 2006 by The McGraw­Hill Companies, Inc. All rights reserved. Alternative and Null Hypotheses Inferential statistics test the likelihood that the alternative hypothesis is true and the null hypothesis is not Significance level of .05 is generally the criterion for this decision – If p .05, then alternative hypothesis accepted – If p > .05, then null hypothesis is retained 3 © 2006 by The McGraw­Hill Companies, Inc. All rights reserved. Four Analytical Steps 1. Statistical test determines if a relationship exists 2. Examine results to determine if the relationship found is the one predicted 3. Is the relationship significant? 4. Evaluate the process and procedures of collecting data 4 © 2006 by The McGraw­Hill Companies, Inc. All rights reserved. Correlation Also known as Pearson product-moment correlation coefficient Represented by r Correlation reveals one of the following: – Scores on both variables increase or decrease – Scores on one variable increase while scores on the other variable decrease – There is no pattern or relationship 5 © 2006 by The McGraw­Hill Companies, Inc. All rights reserved. ... - tailieumienphi.vn