Question

this assignment must be submitted before the 1.3 quiz. late work will not be accepted. section 1.3: experiments and observational studies example 1: association or causation? for each of the following statements, indicate whether the statement implies causation or just indicates association without causation. a) students who take more ap classes in high school tend to have higher college gpas. (source: college board, “ap and college success,” 2020) b) want to boost your memory? drink more water! (source: edmonds, c. j., et al. “water consumption, memory, and attention: a randomized trial.” appetite, 2013) c) people who volunteer regularly report better mental health outcomes. (source: mayo clinic, “volunteering and its surprising benefits,” 2022) example 2: smartphones and sleep a study found a strong negative association between smartphone use before bedtime and average hours of sleep among u.s. teens. teens with higher daily screen time tended to sleep fewer hours. (source: pew research center, “teens, social media and technology 2022”) a) does this mean we can improve teen sleep by simply taking away all smartphones? b) describe a possible confounding variable in this association. example 3: fast food and obesity a politician claimed in 2019 that living near fast food restaurants causes obesity. they noted that a city with the most fast food outlets also had the highest obesity rate. (source: u.s. centers for disease control and prevention, national health statistics reports, 2019) a) what common mistake is the politician making? b) describe a possible confounding variable in this association.

Explanation:

Example 1:

a)

This shows an association. Just because students take more AP - classes and have higher college GPAs doesn't mean taking AP - classes causes higher GPAs. There could be other factors like a student's natural academic ability.

b)

This implies causation. The statement "Want to boost your memory? Drink more water!" suggests that drinking water directly causes an increase in memory.

c)

This shows an association. Regular volunteering and better mental - health outcomes are related, but volunteering may not be the direct cause of better mental health. There could be other factors like the social interaction aspect of volunteering.

Example 2:

a)

No. Just because there is a negative association between smartphone use before bedtime and average hours of sleep among U.S. teens doesn't mean taking away all smartphones will improve teen sleep. There could be other factors affecting sleep, and smartphones may not be the sole cause of sleep problems.

b)

One possible confounding variable could be stress levels. Teens with higher stress levels may be more likely to use their smartphones before bedtime as a form of distraction and may also have trouble sleeping.

Example 3:

a)

The politician is confusing correlation with causation. Just because a city has a high number of fast - food outlets and a high obesity rate doesn't mean that living near fast - food restaurants causes obesity. There could be other factors at play.

b)

A possible confounding variable could be lack of access to healthy food options. Areas with a high number of fast - food outlets may also lack grocery stores or farmers' markets, making it difficult for residents to access healthy food, which could contribute to obesity.

Answer:

Example 1:

a) Association

b) Causation

c) Association

Example 2:

a) No

b) Stress levels

Example 3:

a) Confusing correlation with causation

b) Lack of access to healthy food options