# correlation, simple question

book 1 page282-283 reading 11 “an increase of one unit in A is associated with exactly the same half-unit increase in B, regardless of the level of A. Even if the slope of the line in the figure were different (but positive), the correlation between the two variables would be 1 as long as all the points lie on that straight line.” sorry asking for such silly question, but i really have no idea on “an increase of one unit in A is associated with exactly the same half - unit increase in B” i remember i saw this question in FinQuiz too anyone can help ? thank you very much

A 1 2 3 4 B 0.5 1 1.5 2 an increase in A of 1 unit is associated with a 0.5 (one Half) increase in B.

thank you very much ~ the question in my mind is why not: A 1 2 3 4 B 0.4 0.8 1.2 1.6 or A 1 2 3 4 B 1 2 3 4

2nd one … 1 2 3 4 and 1 2 3 4 is a 1 unit increase in B is linked to a 1 unit increase in A. 1st one… 1 2 3 4 to 0.4 0.8 etc. is a 1 unit increase in A to a 0.4 increase in B.

thanks cpk, so is it for the 2nd one , the correlation would be 1 too?

if both series A and series B increase - correlation would be +1.

so the rate of increase related to regression coefficient we just know +1 is an absolute proportion increase thank you~