5% Rule

What is the purpose of the 5% Rule?

The purpose of the 5% Rule is to give you the option of eliminating a vertical axis intercept.  When you have a vertical axis intercept that you believe exists only because of error in your data, the 5% Rule can be invoked (if all conditions are met) and the intercept may be dropped from you mathematical equation.

What two conditions need to be met before I can apply the 5% Rule?

The 5% rule can be used if the following requirements are met.

1. You must have a logical belief that the vertical intercept should be zero.

2. The vertical axis intercept error must be less than 5%

How do I calculate the vertical axis intercept error?