Chapter 6: Scatterplots, Association, and Correlation

Question 1

Bivariate Data

Answer 1

Data with two variables. Two quantitative variables are visualized in a scatter plot

Question 2

Explanatory Variable

Answer 2

Variable that predicts, explains, or influences a trend in the response variable

Question 3

Response Variable

Answer 3

The measured outcome. Responds to trends in the explanatory variable

Question 4

Strong Data Vs. Weak Data

Answer 4

Strong: Data closely follows the pattern (Reliable for predictions)
Weak: Data doesn’t follow the pattern (Unreliable for predicitions)

Question 5

How To Describe Linear Relationships

Answer 5

DUCFS
Direction (Postive/Negative)
Unusual features (Outliers & Clusters)
Context
Form (Linear/Non-Linear)
Strength (Strong/Weak)

Question 6

Correlation Coefficient (r)

Answer 6

Gives the direction and magnitude; the strength of a linear relationship (-1<=r<=1)

Question 7

r Relating To Direction & Strength

Answer 7

Negative r = negative correlation
Positive r = positive correlation

r closer to 0 = weaker correlation
|r| closer to 1 = stronger correlation
CORRELATION DOES NOT IMPLY CAUSATION