CHAPTER 4 Correlation Requires Variation

Question 1

What is required to learn about a correlation?

Answer 1

Variation in both variables of interest

Correlation cannot be established without observing variation in both the independent and dependent variables.

Question 2

What is the common mistake people make when trying to establish correlations?

Answer 2

Selecting on the dependent variable

This occurs when only instances of the phenomenon occurring are examined, ignoring cases where it did not occur.

Question 3

What are the four pieces of information needed to determine the correlation between oil production and autocracy?

Answer 3

• Number of autocracies that are major oil producers
• Number of democracies that are major oil producers
• Number of autocracies that are not major oil producers
• Number of democracies that are not major oil producers

Question 4

What does it mean when we say ‘correlation requires variation’?

Answer 4

You must observe variation in both variables to determine correlation

Observing variation in only one variable is insufficient.

Question 5

True or False: It is sufficient to examine only the instances of a phenomenon to establish a correlation.

Answer 5

False

This approach ignores the necessary variation in cases where the phenomenon does not occur.

Question 6

What is the phrase used to describe the variable representing the phenomenon being forecasted or explained?

Answer 6

Dependent variable

Question 7

What is the ‘10,000-hour rule’ proposed by Malcolm Gladwell?

Answer 7

It takes about 10,000 hours of serious practice to master any difficult skill

Gladwell suggests that this practice is a predictor of great success.

Question 8

What flaw exists in Gladwell’s argument regarding the 10,000-hour rule?

Answer 8

He does not consider non-great achievers’ practice habits

This lack of data on non-achievers prevents establishing a correlation.

Question 9

What does the term ‘selecting on the dependent variable’ imply?

Answer 9

Choosing cases based on the value of the dependent variable rather than observing variation

Question 10

In the context of studying financial crises, what mistake do researchers often make?

Answer 10

They examine only previous crises without considering instances where crises did not occur.

Question 11

What is the implication of studying only successful individuals when trying to understand success?

Answer 11

It fails to provide information about those who are not successful

This creates a biased perspective on the factors contributing to success.

Question 12

Fill in the blank: Correlation requires _______.

Answer 12

Variation

Question 13

What is a potential issue with claiming a correlation based on selective examples?

Answer 13

It may mislead conclusions due to lack of comprehensive data

Conclusions drawn from selective examples may not represent the larger population.

Question 14

What is the problem with the claim that drinking a specific beverage caused illness in a group of sick individuals?

Answer 14

The beverage was consumed by both sick and healthy individuals

This demonstrates the importance of variation in establishing a correlation.

Question 15

What is the significance of observing both autocracies and democracies in assessing the correlation with oil production?

Answer 15

It allows for a comprehensive understanding of the correlation

Observing only one type would lead to misleading conclusions.

Question 16

True or False: Gladwell’s evidence supports a definitive causal link between practice and success.

Answer 16

False

Correlation must be established before causality can be considered.

Question 17

What is the 10,000-hour rule?

Answer 17

The idea that extensive practice leads to success, though it is unsubstantiated by data.

Question 18

Who founded the Parents Music Resource Center (PMRC)?

Answer 18

Tipper Gore, among others.

Question 19

What was the PMRC’s primary concern?

Answer 19

The perceived inappropriate content of rock music.

Question 20

What did the PMRC demand for albums with explicit lyrics?

Answer 20

Warning labels.

Question 21

Which song was cited by the PMRC as an example of ‘porn rock’?

Answer 21

Bruce Springsteen’s ‘I’m on Fire’.

Question 22

What were some claims made by Jeff Ling regarding rock music?

Answer 22

It encourages suicide, violent revenge, and sexual violence.

Question 23

What is the structure of Ling’s argument against rock music?

Answer 23

1. Some young people behave regrettably. 2. Those young people listen to terrible rock music. 3. The music must cause the behavior.

Question 24

What did Fredric Wertham testify about comic books in 1954?

Answer 24

He claimed they contributed to moral confusion and violence among youth.

Question 25

What did the U.S. Department of Education and Secret Service find about school shooters?

Answer 25

Many felt bullied and had difficulty coping with losses.

Question 26

What is a key finding about school shooters' behavior prior to attacks?

Answer 26

Most displayed concerning behavior indicating a need for help.

Question 27

What did the 2018 commission report about character education and school shooters?

Answer 27

Many experienced social isolation.

Question 28

True or False: Individuals diagnosed with mental illness are more likely to commit gun crimes.

Answer 28

False.

Question 29

What is a significant issue in the analysis of youth violence according to the text?

Answer 29

Correlation requires variation.

Question 30

What percentage of students in public schools do not graduate on time?

Answer 30

Almost a third.

Question 31

According to the Gates Foundation study, what was the main reason for dropping out of high school?

Answer 31

Classes were not interesting.

Question 32

What percentage of high school dropouts reported finding school uninteresting?

Answer 32

47 percent.

Question 33

What did researchers at Indiana University find about high school students' boredom?

Answer 33

66 percent reported being bored at least every day in class.

Question 34

What problem does the Gates Foundation's research have?

Answer 34

It lacks variation in comparing dropouts to non-dropouts.

Question 35

What did Robert Pape study regarding suicide terrorism?

Answer 35

The motivations behind suicide terrorism in relation to foreign occupation.

Question 36

What correlation did Pape suggest exists between foreign troops and suicide attacks?

Answer 36

The presence of foreign troops leads to more suicide attacks.

Question 37

What does correlation require in studying suicide attacks?

Answer 37

Variation between occupied and non-occupied countries.

Question 38

What did a study find about the likelihood of suicide attacks in occupied countries compared to non-occupied ones?

Answer 38

Less than 1 percentage point difference.

Question 39

What historical examples illustrate the lack of correlation between occupation and suicide terrorism?

Answer 39

British occupation of Ireland and U.S. troops in Germany, Japan, South Korea, etc.

Question 40

What is a common mistake in analyzing suicide attacks?

Answer 40

Selecting on the dependent variable.

Question 41

What mistake does the text illustrate regarding correlation?

Answer 41

Looking for correlation without variation can lead to misleading conclusions. ## Footnote This is exemplified by the analysis of suicide attacks in the 1980s.

Question 42

What was a significant finding about suicide attacks recorded by 1986?

Answer 42

Thirty-three attacks and over one thousand deaths were primarily by Hezbollah against American, Israeli, and French targets in Lebanon.

Question 43

What incorrect conclusion might one draw from the data on suicide attacks in 1986?

Answer 43

That Islam was the key correlate to suicide attacks due to the attackers being Muslim. ## Footnote This ignores the broader context of Muslim-majority countries without similar violence.

Question 44

What was the first suicide attack by a secular group mentioned in the text?

Answer 44

The attack by the Liberation Tigers of Tamil Eelam (Tamil Tigers) in 1987 in Sri Lanka.

Question 45

What does the text suggest about the organization of certain professions?

Answer 45

It can lead to selecting on the dependent variable, as doctors primarily see sick patients.

Question 46

What correlation is questioned regarding bulging discs and back pain?

Answer 46

There is little evidence that bulging discs are correlated with back pain when considering healthy individuals. ## Footnote Studies show that a significant number of people without back pain also have bulging discs.

Question 47

What is a common institutional response following disasters?

Answer 47

Conducting post-mortem analyses to understand what went wrong or right.

Question 48

What is a critical mistake in post-mortem analyses according to the text?

Answer 48

Focusing on what could have been done differently with hindsight rather than assessing decisions based on prior knowledge.

Question 49

What fictional example is used to illustrate post-mortem analysis errors?

Answer 49

A high school band director analyzing competition failures after scheduling intensive rehearsals.

Question 50

What is the main error made by the band director in the post-mortem?

Answer 50

Assuming that intensive rehearsals are the cause of poor performance without considering variation in outcomes.

Question 51

What conclusion can be drawn from the rehearsal strategy data provided?

Answer 51

There is a strong positive correlation between extra rehearsals and performing well in competitions.

Question 52

What disaster is used as a case study in post-mortem analysis?

Answer 52

The Challenger space shuttle explosion in 1986.

Question 53

What crucial factor did engineers predict prior to the Challenger launch?

Answer 53

That cold weather would lead to catastrophic failure due to O-ring seals not being certified for low temperatures.

Question 54

What was the conclusion of the Rogers Commission regarding NASA's decision-making?

Answer 54

Failures in communication and management led to ignoring valid engineering concerns.

Question 55

What is required to assess whether launching the Challenger was a reasonable decision?

Answer 55

Understanding the correlation between scientific concerns and the success of shuttle launches.

Question 56

What essential question should post-mortem commissions ask regarding engineering concerns?

Answer 56

Whether scientifically valid concerns had been raised prior to successful launches.

Question 57

What are some scientifically valid concerns raised by engineers prior to successful space shuttle launches?

Answer 57

Concerns about complex and dangerous undertakings ## Footnote Engineers may raise valid concerns that are not necessarily correlated with launch success.

Question 58

What triggered the financial crisis of 2008?

Answer 58

A crash in the U.S. subprime housing market ## Footnote This crash had widespread effects across the global banking sector.

Question 59

Which book by economists analyzed data on major financial crises over the last 800 years?

Answer 59

This Time Is Different by Carmen M. Reinhart and Kenneth S. Rogoff ## Footnote The book aims to identify early warning indicators of financial crises.

Question 60

What are some key indicators that precede financial crises according to Reinhart and Rogoff?

Answer 60

* Uncommonly large current account deficits * Asset price bubbles * Excessive borrowing ## Footnote These indicators were present in the lead-up to the 2008 financial crisis.

Question 61

What was the U.S. current account deficit as a percentage of GDP in 2006?

Answer 61

Close to 7 percent ## Footnote This was one of the factors leading up to the financial crisis.

Question 62

What is a major flaw in Reinhart and Rogoff's analysis of financial crises?

Answer 62

It does not account for variation in crises ## Footnote Correlation requires understanding both when crises occur and when they do not.

Question 63

What happened in the late 1990s that raises doubts about Reinhart and Rogoff's conclusions?

Answer 63

The U.S. had early warning signs but no financial crisis occurred ## Footnote The dot-com bubble burst but did not lead to a financial crisis.

Question 64

What is the problem with seeking life advice from successful people?

Answer 64

Successful people may not know whether their decisions correlate with success ## Footnote Their introspection lacks variation and may not provide reliable lessons.

Question 65

What does 'selecting on the dependent variable' mean?

Answer 65

Examining only instances when the phenomenon of interest occurred ## Footnote This approach does not allow for proper analysis of correlation.

Question 66

What is a recommended practice to avoid looking for correlation without variation?

Answer 66

Consider filling in all four cells of a two-by-two table ## Footnote This helps in visualizing the relationship between variables.

Question 67

What quantitative technique is important for measuring correlations?

Answer 67

Regression ## Footnote This technique is discussed in more detail in chapter 5.

Question 68

Fill in the blank: Correlation requires _______.

Answer 68

[variation] ## Footnote Without variation, establishing correlation is not possible.

Question 69

True or False: Most top-performing schools have small student bodies.

Answer 69

True ## Footnote This statement suggests a correlation but requires further analysis.

Question 70

True or False: Married people are typically happier than unmarried people.

Answer 70

True ## Footnote This statement implies a correlation that needs to be examined for variation.

Question 71

What proportion of the world’s population has a college degree?

Answer 71

About 7 percent ## Footnote This statistic is relevant when assessing correlations related to education and success.

Question 72

What might be the correlation between dropping out of college and becoming a billionaire?

Answer 72

It is unclear without examining more data ## Footnote The analysis should consider the variation in outcomes among college dropouts.

Question 73

What is a potential consequence of only looking at successful college dropouts?

Answer 73

It may lead to a biased understanding of the correlation with success ## Footnote This issue arises when ignoring the broader population of college attendees.