### Home > INT1 > Chapter 7 > Lesson 7.2.3 > Problem7-111

7-111.

This problem is a checkpoint for interpreting associations. It will be referred to as Checkpoint 7.

A random sample of competitive cyclists had their maximum sustainable power output (watts) versus $\text{VO}_{2}$max tested. Their data is shown in the table below. Note: $\text{VO}_{2}$max, also called “aerobic capacity”, is a measure of how much oxygen your body uses when exercising at a maximal effort for an extended period of time.

1. Create a model by finding the LSRL. Sketch the graph and the LSRL.

2. What power does the model predict for the cyclist that has a $\text{VO}_{2}$max of $43$ ml/kg/min? Consider the precision of the measurements in the table and use an appropriate precision in your result.

3. Find the residual for the cyclist in part (b).

4. Find the correlation coefficient and interpret it.

5. Describe the association. Provide numerical values for direction and strength and interpret them in context.

Check your answers by referring to the Checkpoint 7 materials located at the back of your book.

 $\text{VO}_{2}$max (ml/kg/min) Power (watts) $54$ $292$ $51$ $362$ $49$ $280$ $43$ $293$ $53$ $280$ $59$ $413$ $64$ $358$ $58$ $293$ $56$ $342$ $55$ $335$ checksum $542$ checksum $3248$

Ideally, at this point you are comfortable working with these types of problems and can solve them correctly.  If you feel that you need more confidence when solving these types of problems, then review the Checkpoint 7 materials and try the practice problems provided.  From this point on, you will be expected to do problems like these correctly and with confidence.

Answers and extra practice are located in the back of your printed textbook or in the Reference Tab of your eBook.
If you have an eBook for INT1, login and then click the following link: Checkpoint 7: Interpreting Associations