Test for Association. -As the Carbon Content in Steel Increases, Its Ductility Tends

Test for association.
-As the carbon content in steel increases, its ductility tends to decrease. A researcher at
A steel company measures carbon content and ductility for a sample of 15 types of steel
Resulting in a correlation of -0.640. The calculated value of the t-statistic to test for a
Significant association between carbon content and ductility is

A) -3.01
B) 4.692
C) -4.692
D) 5.09
E) 2.363