Solution-
A correlation coefficient is a statistical measure of the degree to which changes to the value of one variable affects change to the value of another.
Correlation coefficients are expressed as values between +1 and -1. A
coefficient of +1 indicates a perfect positive correlation: A change in the value of one variable will affect a change in the same direction in the second variable.
A coefficient of -1 indicates a perfect negative correlation: A change in the value of one variable predicts a change in the opposite direction in the second variable.
Lesser degrees of correlation are expressed as non-zero decimals. A coefficient of zero indicates there is no relationship between fluctuations of the variables.
∴ It's a positive correlation of 0.52, so as the box gets bigger the cost goes up. However, the cost goes up at only half the rate of increase of the size (bigger boxes are cheaper per unit volume).