Clearly the y-axis in the following graph or scatter plot represents the Stretch length (in cms) and x-axis denotes the value stretch force (in pounds) i.e. the force applied to the string in pounds.
The number 1 in the equation mean in this context:
That the spring is stretched 1 inch when no force was applied to it.
since the number 1 on the y-axis i.e when x=0 i.e. no force is applied to it.
