Chapter 8: Bivariate Correlational Research Flashcards

1
Q

What is the difference between experimental methods and correlation?

A
  • Experimental methods test if changes to IV causes changes to DV score. Ex. Does coffee make you anxious?
  • Correlations are descriptive methods. Look at behaviors as they occur. Ex. Is there a relationship between feeling anxiety (X) and coffee drinking (Y)?
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2
Q

What do correlations do?

A
  • Evalulate the strength of a relationship
  • The mathematical measure of an association between 2 variables
  • Do NOT establish cause
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3
Q

When would you use a correlation?

A
  • To make a prediction
  • For validity: If you made a new IQ test, to determine how good it is, you could compare results on the new test (X) to results on another valid test (Y)
  • For reliability: Measurements are stable if they produce similar results across situations. Ex. To see if your score today is correlated with your score next week
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4
Q

What are some association claims supported by correlational research? Why aren’t they causal statements?

A
  • Meaningful conversations linked to happier people
  • Couples who meet online have better marriages.
  • Tehse are not causal statements because there was no random assignment to different groups
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5
Q

Bivariate correlation/association

A
  • Three kinds: pos, neg, zero
  • 2 variables (X and Y). Each participant will have a score on both variables. Asks: Is there a relationship between the way one variable changes and the way a second variable changes?
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6
Q

What does a scatterplot do?

A

Represents the score for each participant on both variables

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7
Q

Cacioppo et al, 2013

A
  • Found that ouples who meet online tend to have between marriages.
  • Emailed surveys asking “How did you meet?” and the Couples Satisfaction Index (CSI)
  • 19,000 respondents… people who met online tended to score slightly higher on CSI
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8
Q

What two pieces of information does the corrleation coefficient tell you?

A
  • Strength of the correlation
  • Direction of the correlation

Is a value between -1 and 1

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9
Q

How does the correlation coefficient (r) tell you the strenght of the correlation?

A
  • Closer to +/-1.0= strong relationship
  • Closer to +/- 0.01= weak relationship
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10
Q

How does the correlation coefficient (r) tell you the direction of the correlation?

A
  • Positive: values increase and decrease together
  • Negative: one value increases, the other decreases
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11
Q

How to visualize associations with categorical data?

A
  • Ex: Did you meet online? Categories are yes and no.
  • Scatter plots can still be useful, as you can seee a higher density of dots in online.
  • But bar graphs are usually more helpful for categorical variables
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12
Q

Do correlational studies establish internal validity?

A

NO

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13
Q

What is construct validity?

A
  • the degree to which a test or measurement tool accurately assesses the theoretical concept or “construct” it is intended to measure
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14
Q

How can you determine construct validity of association claims?

A
  • Because association claims describe the relationship between 2 variables, it is reasonable to ask about the construct validity of each variable.
  • Can ask: How well were each of the variables measured? Does the measure have good reliability? Is it measuring what it intends to measure? Face, discriminant, and convergent validity?
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15
Q

Using the CSI example, what questions should you ask to determine its’ construct validity?

A
  • Does it have good internal reliability?
  • Does it correlate with other measures of marital happiness?
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16
Q

What is face validity?

A
  • Compared to construct validity, which examines whether the tool truly captures the underlying theoretical construct, face validity is a more superficial assessment based on how the tool appears on the surface
  • Face validity is a subjective evaulation of whether a test “looks like” it measures what it intends to
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17
Q

What is discriminant validity?

A
  • The extent to which a test or measurement tool accurately differentiates between distinct constructs
  • Meaning, it should now show high correlations with tests designed to measure different, unrelated concepts
  • Demonstrates that a test is measuring what it intends to measure and not picking up on other unintended constructs
18
Q

What is convergent validity?

A
  • Measure of how closely a test or instrument correlates with other tests that measure the same or similar constructs
  • Established when there is a strong positive correlation between the results of a test and other tests that measure the same construct
19
Q

Questions to ask to determine statistical validity

A
  • How well do the data support the conclusion?
  • How strong is the relationship?
  • Effect size (the strength of a relationship between two or more variables)?
20
Q

Statistical validity and effect size

A
  • All else being equal, a larger effect size is better/more important
  • But a small effect size over multiple observations can also be important (Ex. taking 0.5 sceonds off an olympic athlete’s sprint time)
21
Q

Statistical Validity: What is aggregation and what are some examples

A
  • Aggregation: small effect sizes can compound over many observations
  • Ex. Baseball: MLB players have higher probability (r=0.05 of getting to a base on any given turn at bat compared to minor league baseball. This is a huge difference over 550 turns at bat.
  • Ex. Agreeableness: Agreeableness= better social interactions (r=0.07) in mid size uni first semester. But there are 100s of interactions in the first few weeks, so that is many ore positive interactions
22
Q

Aggregation: Many participants

A
  • Teens in US high schools with a growth mindset (can be smarter through effort and good learning strategies) have better grades (r=0.05)
  • If implemented at scale, this could be enough to prevent 79,000 teens from scoring in F and D range
23
Q

Statistical validity: How precise is the estimate?

A
  • How right/wrong could your estimate possible be?
  • 95% confidence interval= margin of error (range) of the estimate. Included true values that will be obtained 95% of the time
24
Q

Confidence Interval Example

A
  • Time spent sitting and medial temporal lobe thickness
  • R=-0.37 [CI=-0.07, -0.64]
  • Notice range does not include zero. When it does contain zero, it is possible there is no relationship

really big range bc data only represent 35 ppl

25
Q

Statistical Validity: Sample size and precision

A
  • When samples are small it is less stable
  • Outliers have a bigger CI
  • Smaller samples have bigger CIs
  • Bigger samples have smaller and more precise CIs
26
Q

Statistical validity: replication

A
  • Important to see if the study has been replicated.
  • Ex (Milek et al 2018) found there is a relationship between deep talk and overall wellbeing.
  • Ran repeatedly… 4/5 reflect a positive relationship
27
Q

Statistical Validity: outliers

A
  • Can the results be due to an extreme score?
  • Depending on the variable and the number of observations, a single score can skew the results
  • In association claims, outliers have a bigger impact when they are extreme on both variables (ex someone who is v tall and v heavy)
  • Outliers matter most when the sample is small
28
Q

Statistical Validity: Range of data

A
  • If there is not a fully represented range on one of the variables it can make the effect seem smaller
  • Can apply at any time one of the variables has little variance
  • SAT scores are predictive of performance in 1st year (r=0.33) but also only includes ppl w/ scores >1200. When you expand the range the correlation gets stronger
29
Q

Can we make causal inference from associations/What are the three criteria for causation?

A
  1. Covariance of cause and effect
  2. Temporal precendence- have a directionality problem
  3. Internal validity- problem w third variable
30
Q

Why does correlation not equal causation?

A
  • Correlations are descriptive, not experimental
  • Often there is another variable that is influencing X and Y
31
Q

Correlation does not equal causation example

A
  • Are disney princess movies related to agreement with female empowerment?
  • 3rd variable; boys who watch these likely have sisters
32
Q

What type of test is correlation?

A
  • Descriptive, set up to describe data
  • Not set up to ask “why” questions
  • Some very stange things are closely correlated
33
Q

Weird correlations

A
  • Ppl who drowned after falling out of a fishing boat and marriage rate in kentucky
  • Searches for JK rowling and coca cola stock price
34
Q

What is evaluative conditioning?

A

Pairing products with another thing people like

35
Q

Why would someone think correlation = causation?

A
  • This tendency reflects a bias of brains
  • The brain is a pattern seeker, and likes finding causal relationships even when none exist
  • The brain is neurologically tuned to notice when things occur together (Hebb Rule: neurons that fire together wire together)
  • We use statistics to overcome our biases
36
Q

Internal validity w association claims: the third variable problem

A
  • Height and hair length= negative correlation (but due to 3rd variable- gender)
  • But 3rd variable is not always a problem (height and weight- despite gender, generally taller women weigh more and taller men also weigh more)
37
Q

What is a spurious association?

A

The association is there but it is not “real”

38
Q

Association claims and external validity

A
  • Can an association be generalized? To other places, ppl, and times?
  • Size of sample matters less than how participants were selected. Random assignment is best
39
Q

What is a moderating variable?

A
  • When the level of a variable changes because of the level of another variable
  • A 3rd variable that influences strength or direction of the relationship between X and Y
  • Suggest that the relationship between 2 variables changes bc of the moderator
40
Q

Moderating variable: fandom example

A
  • The better the team does, the more tickets sold
  • But, residential mobility matters, as it increases fairweather fans
  • Moderating variable= residential mobility