Chapter 13: Regression and Correlation Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is correlation and regression?

A

Statistical techniques are often used in relation with one another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What can you do with correlation and regression?

A

quantify the strength and direction of an association between variables

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is covary?

A

Two random variables are associated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is regression?

A

For any given value of x we can predict the corresponding value of y, specific predictions based on an association

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the correlation coefficient?

A

Number that quantifies the strength and direction of an association between variables

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What numbers are correlations between?

A

1 and -1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the measures of association?

A

The variety of correlation coefficients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What do correlations measure?

A

Relationship between 2 variables (x and y)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Suppose that you have access to hospital records on patient age and their number of days spent in hospital. Your most appropriate measure of association would likely be ________.

A

Pearsons r

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What can you say if no pattern appears to exist between variables?

A

Statistically independent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the strength variation in correlation?

A

0 and +- 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does a stronger pattern or association mean?

A

Larger the correlation coefficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

There is no such thing as a zero correlation.

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

A correlation coefficient distinguishes between independent and dependent variables.

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Are a coefficient of -.35 and +.35 equally strong?

A

Yes can think of it as a continuum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the relationship between positive and negative correlations?

A

Positive go together, in negative they move apart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do scatterplots plot?

A

Interval or ratio level data onto a graph in a case-by-case manner

18
Q

What does the horizontal axis represent?

A

Predictor variable

19
Q

What does the vertical axis stand for?

A

Criterion variable

20
Q

What is the line of best fit?

A

straight line that best represents data on scatter plot (regression line), nature of relation between two variables, eyeball method, decides if it is linear

21
Q

What happens if a straight line can’t be drawn through the data points?

A

There may be no relationship at all

22
Q

What are scatterplots very useful for spotting?

A

Outliers in data

23
Q

What do outliers have a significant impact on?

A

Correlation coefficients

24
Q

What do scatterplots tell us in regard to calculations?

A

Whether or not calculating pearsons r is appropriate

25
Q

What are the requirements for pearsons r?

A

Random sampling, continuous interval or ratio data, normally distributed variables, no significant outliers, linear

26
Q

What can pearsons r not detect?

A

Non-linear associations

27
Q

Study The Who grows up to be a philanderer thing cause it is mentioned a LOT

A
28
Q

What is a advantage of Pearson coefficients?

A

Possess a common metric, compare strength of relationships with one another

29
Q

What is the remaining percentage 100-r^2?

A

Unexplained variation

30
Q

What is unexplained variation?

A

Variation in y is accounted for by some variable that isn’t x

31
Q

What do you use when you cant use Pearsons r?

A

Rank correlation

32
Q

What is monotonicity?

A

Whether or not one set of scores tends to increase or decrease along with another set (linear)

33
Q

What are non-monotonic associations?

A

Scores can’t increase together then decrease

34
Q

What is a spurious correlation?

A

Association is caused by a third variable that affects both the associations two variables simultaneously;

35
Q

What is reverse causation?

A

Might think x causes y but actually y causes x

36
Q

What is the post-hoc fallacy?

A

If B followed A then A must have caused B

37
Q

What happens with stronger associations?

A

The more likely it is causal

38
Q

What is empirical support?

A

Gathered evidence using our senses

39
Q

What is the slope?

A

Steepness of the line of best fit, amount of change in y for every change in x (descriptive statistic)

40
Q

What is the intercept?

A

Point regression line crosses y axis when x=0

41
Q

What are the steps of the regression equation?

A

Calculate slope (b), calculate intercept (a), using value of x solve for y