Correlation Flashcards
(9 cards)
1
Q
Describing a scatterplot
A
- Direction
- Form
- Strength
2
Q
r
A
numerical value that measures stength of correlation
1 = perfect positive correlation
-1 = perfect negative correlation
[-1,1]
3
Q
Linear Regression
A
y = a + bx
4
Q
Extrapolation
A
using regression lines to make predictions ooutside data range
-> unreliable, should be avoided
5
Q
Residuals
A
the difference between observed and expected values
observed - expected
6
Q
Residual Plot
A
Plots residuals of each point on y-axis
If linear correlation: no noticeable form on residual plot
7
Q
s
A
Standard Deviation of Residuals
Lower s = more accurate
Measured in y units
8
Q
r^2
A
measures what % of variation in y is explained by x
Higher r^2 = more accurate
no units
9
Q
Influential points
A
Outliers on x-axis that have strong influence on regression line
