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?
   1. What sort of relationship is displayed in the scatter plot below?

("Scatter Plot in Exercises" by Judy Schmitt is licensed underCC BY-NC-SA 4.0.)

1. What is the direction and magnitude of the following correlation coefficients?
   1. .81
   2. .40
   3. .15
   4. .08
   5. .29
2. A scatter plot with the following data:

Hours Studying	Overall Class Performance
0.62	2.02
1.50	4.62
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

1. In the following correlation matrix, what is the relationship (number, direction, and magnitude) between
   1. Pay and Satisfaction
   2. 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

1. Using the data from Problem 7, test for a statistically significant relationship between the variables.
2. 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 thea= .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