answers

Chapter 12 Activity Instructions: Show all work when applicable. This can be done online or by hand. Once completed, upload activity to Canvas as a Word or PDF file or take a picture if done by hand. 1. What does a correlation assess? 2. What are the three characteristics of a correlation coefficient? 3. What is the difference between covariance and correlation? 4. Why is it important to visualize correlational data in a scatter plot before performing analyses? 5. What sort of relationship is displayed in the scatter plot below? 30.0 27.5 25.0 : . 20.0 150 17.5 20.0 22.5 25.0 6. What is the direction and magnitude of the following correlation coefficients? a. -.81 b. .40 c. .15 d. -.08 e. .29 7. Create a scatter plot from the following data: Hours Studying Overall Class Performance 0.62 2.02 1.50 1.62 0.34 2.60 0.97 1.59 3.54 4.67 0.69 2.52 1.53 2.28 0.32 1.68 1.94 2.50 1.25 4.04 1.42 2.63 3.07 3.53 3.99 3.90 1.73 2.75 1.29 2.95 8. In the following correlation matrix, what is the relationship (number, direction, and magnitude) between a. Pay and Satisfaction b. Stress and Health WORKPLACE Pay Satisfaction Stress Health Pay 1.00 Satisfaction .68 1.00 Stress -02 -.23 1.00 Health 05 15 -.48 1.00 9. Using the data from Problem 7, test for a statistically significant relationship between the variables. 10. Researchers investigated mother-infant vocalizations in several cultures to determine the extent to which such vocal interactions are true for all humans or culture-specific. They thought that mothers who talked more would have babies who vocalized (babbled) more. They observed mothers and infants for 50 minutes and recorded the number of times the mother spoke and the baby vocalized during the observation session. Data below are for 10 mother-infant pairs in Cameroon. Test the hypothesis at the a = .05 level using the four-step hypothesis testing procedure. Mother Spoke Baby Vocalized 80 110 60 110 120 100 100 130 100 140 90 115 80 150 40 130 80 95 50 50