NOT true about co-relation is-
Ref:Parks 23rd edition pg 852 In order to find out whether there is significant association or not between the two variables , coefficient or Corelation is calculated . r lies between -1 and +1 r near -1 : indicates strong negative correlation . r = 0 : indicates no association r near +1: indicates strong positive correlation. Note: correlation does not necessarily prove causation .
Doesn't tell about causation
Tells about risk of the disease
-1.0 correlation shows linear relationship
Tells association between two variables
Biostatistics