Could you help to explain?

which is the best choice?

thanks a lot~

The shear strength of the bond between two types of propellant is important in the manufacturing of a rocket motor. An investigator is interested in whether the age of the propellant is related to the shear strength?Data from 20 paired observations were used to fit a aleast-squares simple linear regression model predicting shear strength from propellant age (in weeks).The equation for the regression is given byy

^

=100038x

y^=100038x.What is the correct interpretation of the slope parameter?

Each additional week of age of the propellant is associated with a 38 unit decrease in shear strength.

Each additional unit of shear strength is associated with a 38 week increase in theage of the propellant.

Each additional week of age of the propellant is associated with a 38 unit increase in shear strength.

Each additional unit of shear strength is associated with a 38 week decreasein the age of thepropellant.