Section 4.2 - Vocabulary and Understanding

An _____ observes individuals and measures variables of interest but does not attempt to influence the responses.

• observational study

• experiment

Tags

CCSS.HSS.IC.B.3

An _____ deliberately imposes some treatment on individuals to measure their responses.

• observational study

• experiment

Tags

CCSS.L.11-12.6

CCSS.L.8.6

CCSS.L.9-10.6

CCSS.W.11-12.2D

CCSS.W.9-10.2D

Confounding occurs when:

• two variables are associated in such a way that their effects on a response variable cannot be distinguished from each other.

• a specific condition is applied to the individuals in an experiment.

Does reducing screen brightness increase batter life in laptop computers? To find out, you buy 30 new MacBook Pros from the Apple Store in The Woodlands. You chose 15 of the MacBooks at random and adjusted their screens to the brightest setting. You then measured how long each MacBook's battery lasted. Was this an observational study or an experiment?

• You conducted an experiment because a treatment (the brightness of the screen) was imposed on the laptops.

• You conducted an observational study because you observed the treatment response imposed on the laptops.

• You conducted an observation study because a treatment (the brightness of the screen) was imposed on computers, not subjects.

• You conducted an experiment because a treatment (the brightness of the screen) was imposed on computers, not subjects.

Tags

CCSS.HSS.IC.B.3

Does eating dinner with their families improve students' academic performance? According to an ABC News article, "Teenagers who eat with their families at least five times a week are more likely to get better grades in school." This finding was based on a sample survey conducted by researchers at Columbia University.

Was this an observation study or an experiment?

• This was an observational study because there was no treatment meaning students were not assigned to eat a particular number of meals with their family per week.

• This was an experiment because there was no treatment meaning students were not assigned to eat a particular number of meals with their family per week.

Does eating dinner with their families improve students' academic performance? According to an ABC News article, "Teenagers who eat with their families at least five times a week are more likely to get better grades in school." This finding was based on a sample survey conducted by researchers at Columbia University.

What are the explanatory variable and response variable?

• The explanatory variable is the number of meals per week eaten with their family.

• The response variable is the subjects GPA.

• The response variable is the number of meals per week eaten with their family.

• The explanatory variable is the subjects GPA.

Tags

CCSS.HSS.ID.C.9

Does eating dinner with their families improve students' academic performance? According to an ABC News article, "Teenagers who eat with their families at least five times a week are more likely to get better grades in school." This finding was based on a sample survey conducted by researchers at Columbia University.

Can you establish a cause-and-effect relationship with this study?

• No. There are probably other variables that influence the response variable. Students may have a part-time job which may be confounded with the whether families eat dinner together.

• No. There is not enough information given to calculate a correlation coefficient so we can determine a correlation between the two variables.

• Yes. There are probably not other variables that influence the response variable.

• Yes. There are probably not other variables that influence the explanatory variable.

Tags

CCSS.HSS.ID.C.9

Does reducing screen brightness increase batter life in laptop computers? To find out, you buy 30 new MacBook Pros from the Apple Store in The Woodlands. You chose 15 of the MacBooks at random and adjusted their screens to the brightest setting. You then measured how long each MacBook's battery lasted. What is the treatment in this study?

• The treatment is that the laptops are Apple.

• The treatment is that the laptops are from the Apple Store in The Woodlands.

• The treatment is the brightness setting on the MacBooks.

• The treatment is how long each Macbook's battery lasted.

When our goal is to understand cause and effect relationships, experiments are the only source of convincing data.

• True

• False

Tags

CCSS.RI.9-10.4

CCSS.RI.9-10.4

CCSS.RI.11-12.4

CCSS.RI.7.4

CCSS.RI.8.4

A _____ measures the outcome of a study.

• response variable

• explanatory variable

Tags

CCSS.HSS.ID.C.9