arc/notes
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

vault backup: 2023-12-13 14:08:19

Browse Source
This commit is contained in:
zleyyij 2023-12-13 14:08:19 -07:00
parent 1eb0897c9c
commit 572b67c845
1 changed files with 17 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
education/statistics/Correlation and Regression.md
View File

@ -3,11 +3,24 @@
# Correlation
## Scatter Diagrams
A scatter diagram or scatter plot shows the relationship between two variables. One variable is on the X axis, the other on the Y axis.
If a scatter diagram is football shaped, it can be summarized using the 5-number summary:
| Variable | Description |
| -- | -- |
| $ave_x$ | |
| $SD_x$| |
| $ave_y$ |
| $SD_y$ | |
| $r$ | |
### Association
- Positive association is demonstrated when the dots are trend upward as $x$ increases.
- Negative association is demonstrated when the the dots trend downward as $x$ increases.
- Strong association is demonstrated when dots are clustered tightly together along a line.
- Weak association is demonstrated when dots are not clustered tightly.
- Positive association is demonstrated when the dots are trend upward as $x$ increases ($r$ is positive).
- Negative association is demonstrated when the the dots trend downward as $x$ increases ($r$ is negative).
- Strong association is demonstrated when dots are clustered tightly together along a line ($|r|$ is closer to 1).
- Weak association is demonstrated when dots are not clustered tightly. ($|r|$ is closer to 0)
## Correlation
Correlation is between `-1` and `1`. Correlation near 1 means tight clustering, and correlation near 0 means loose clustering. $r$ is -1 if the points are on a line with negative slope, $r$ is positive 1 if the points are on a line with a positive slope. As $|r|$ gets closer to 1, the line points cluster more tightly around a line.