Download - Relationship between Two Numerical Variables
RELATIONSHIP BETWEEN TWO NUMERICAL VARIABLES
By Farrokh Alemi, Ph.D.
Investigators are often interested in relationship between variables
Relationships
Multiple observations needed
Anecdotal Data
I have smoked all my life and I do not have cancer
Anecdotal Data
Relationships
Independent X & Y
Explanatory Variable𝐸𝑥𝑝𝑙𝑎𝑛𝑎𝑡𝑜𝑟𝑦 𝑣𝑎𝑟𝑖𝑎𝑏𝑙𝑒 𝑚𝑖𝑔ℎ𝑡 𝑎𝑓𝑓𝑒𝑐𝑡
ሱۛ ۛ ۛ ۛ ۛ ۛ ۛ ۛ ሮ 𝑅𝑒𝑠𝑝𝑜𝑛𝑠𝑒
Association Is Not Causation
Causation Requires: Association Sequence (causes preceded effects) Mechanism Counter factual (no effect when causes
are absent)
Causation Requires: Association Sequence (causes preceded effects) Mechanism Counter factual (no effect when causes
are absent)
Causation Requires: Association Sequence (causes preceded effects) Mechanism Counter factual (no effect when causes
are absent)
Causation Requires: Association Sequence (causes preceded effects) Mechanism Counter factual (no effect when causes
are absent)
Association Is Not Causation
A Scatterplot can show the association between two variables
Take Home Message
Do one: