If the correlation between x and y is larger than 0.5, then a linear equation is appropriate to describe the association.

a. The statement is false. The correlation must be greater than 0.9 to indicate that a linear equation is appropriate to describe the association.
b. The statement is false. The correlation must be greater than the critical value, which cannot be found because n is unknown, to indicate that a linear equation is appropriate to describe the association.
c. The statement is true.
d. The statement is false. A correlation over 0.5 does not necessarily indicate that a linear equation is appropriate to describe the association. It is possible for relationships other than linear relationships to have correlations of over 0.5.