Societies did not develop monetary commodity systems until the mid-nineteenth century. is it true or false?

Match the item to the definition: indirect correlation, correlational research, correlational research, covary, pearson correlation coefficient, pearson correlation coefficient, direct correlation a. used to describe the relationship between two or more naturally occurring variables b. determines whether scores on the two variables covary c. whether two variables vary or change together d. denoted by the symbol "r" e. provides information about the sign (direction) and magnitude(strength) of the linear relationship. f. when the correlation is positiveg. when the correlation is negative