L2

Question 1

Bivariate Analysis

Answer 1

Relationship btw. two variables

Question 2

Graphical descriptive techniques of the bivariate analysis

Answer 2

• cross-classification table (nominal/ordinal data)
• -> stacked and clustered bar chart
• scatter plots (interval data)

Question 3

Numerical descriptive techniques

Answer 3

covariance and correlation (interval data)

Question 4

Scatter plot

Answer 4

to display values for two interval variables in a Cartesian coordinate system

Question 5

What does a negative slope of a linear line indicate?

Answer 5

negative linear relationship

Question 6

covariance

Answer 6

measures the direction of a linear relationship btw two variables
+= positive linear relationship
-= negative linear relationship

Question 7

Does the magnitude of the covariance indicate the strength of a linear relationship?

Answer 7

No, the covariance’s magnitude depends on the unit of the variables

Question 8

What gives us the strength of the relationship btw. two variables?

Answer 8

• the coefficient of correlation p (Rho) it can be -1 to 1

Question 9

What does p (Rho; correlation coefficient) close to -1 indicate?

Answer 9

strong negative correlation (perfect downward sloping line)

Question 10

What does p close to 1 indicate

Answer 10

strong positive correlation

Question 11

what does around 0 indicate?

Answer 11

no linear relationship; does not imply a lack of any relationship because a quadratic relationship has a relationship (looks like a hill) but not a linear one

Question 12

What is a spurious correlation?

Answer 12

If Z causes X andY at the same time or the relationship btw. X and Y is pure coincidence