A regression analysis between sales (Y in $1000) and advertising (X in dollars) resulted in the following equation
= 30,000 + 4 X
The above equation implies that an
◦
increase of $4 in advertising is associated with an increase of $4,000 in sales
◦
increase of $1 in advertising is associated with an increase of $4 in sales
◦
increase of $1 in advertising is associated with an increase of $34,000 in sales
◦
increase of $1 in advertising is associated with an increase of $4,000 in sales