11. Correlation

Why is it important to perform graphical as well as analytical analyses when analyzing relations between two quantitative variables?

True or False: Correlation implies causation.

Graphical Analysis In Exercises 11–14, determine whether there is a perfect positive linear correlation, a strong positive linear correlation, a perfect negative linear correlation, a strong negative linear correlation, or no linear correlation between the variables.

In Exercises 13–16, write a statement that interprets the P-value and includes a conclusion about linear correlation.

Using the data from Exercise 6 “Airport Data Speeds,” the P-value is 0.003.

Writing Use an appropriate research source to find a real-life data set with the indicated cause-and-effect relationship. Write a paragraph describing each variable and explain why you think the variables have the indicated cause-and-effect relationship.

c. Coincidence: The relationship between the variables is a coincidence.

Suppose you work a part-time job and earn \$15 per hour. Draw a scatter diagram that might represent the relation between your gross pay and hours worked. Is this a deterministic relation or a probabilistic relation?

"In studies of monozygotic (identical) twins, the correlation between intelligence (IQ) scores is 0.85.

a. Who are the individuals in this study?"

Randomization

For Exercises 33–36, repeat the indicated exercise using the resampling method of randomization.

Powerball Jackpots and Tickets Sold Exercise 14