How do you calculate a regression line only using the standard deviation and the mean?

Answer 1

You can't. You also need the correlation coefficient, which requires the data itself.

The equation of the regression line is y = ax+b, where

a = r*Sy/Sx
b = My-a*Mx

and
r = correlation coefficient
Sy,Sx = standard deviations of y and x
My,Mx = means of y and x