What can be inferred from a correlation coefficient of 0.15 between septic tank density and ground water nitrate concentrations?

A correlation coefficient of 0.15 suggests a very weak positive relationship between septic tank density and groundwater nitrate concentrations. This value indicates that as the density of septic tanks increases, there is only a slight tendency for nitrate concentrations to increase, but the strength of this relationship is minimal.

In the context of statistical analysis, a coefficient close to zero implies that there is little to no linear relationship between the two variables being studied. Therefore, the interpretation aligns with the idea that while there may be some degree of association, it is not strong enough to conclude that septic tanks have a significant impact on nitrate levels in groundwater.

A coefficient of 0.15 does not support the notion that septic tanks contribute significantly to nitrate concerns or that there is a strong positive relationship between the two. Rather, it indicates a lack of correlation that would warrant further investigation but does not affirm any substantial link.