Page 216 - IM_Algebra1_FL Print Sample.pdf

Solution
a. They are weakly correlated because the correlation coe cient is near zero. It appears that as the number of students attending one of these clubs increases, the number of students attending the other club tends to decrease.
b. Sample response: There is not evidence for causality. Any relationship between the variables is likely due to another cause such as other events at the school con icting with the club meeting time.
Problem Statement
A news website shows a scatter plot with a negative relationship between the amount of sugar eaten and happiness levels. The headline reads, “Eating sugar causes happiness to decrease!”
a. What is wrong with this claim?
b. What is a better headline for this information?
Solution
a. Scatter plots do not provide enough evidence for causality, only association.
b. Sample response: A better headline would be “Eating sugar is correlated with lower happiness levels, but we don’t know why!”
Problem Statement
A news headline claims that “Essential Oils Cause Hormone Levels to Drop.” They show a scatter plot displaying a weak negative relationship ( ) between essential oil use and hormone levels.
a. What is wrong with this claim?
b. What is a better headline for this information?
Solution
Sample response:
a. The weak relationship means there is likely not even an association and certainly not causation.
b. The headline should say, “Essential Oil Use and Hormone Levels are Unrelated.”
Unit 3 Lesson 9 Practice Problems 149