An inverse relationship is one in which the value of one parameter tends to decrease as the value of the other parameter in the relationship increases. It is often described as a negative relationship.
Imagine the age of a car and its value. In general terms, as a car increases in age its value will decrease (the amount of miles driven per unit of time also factors in to this, but we will leave that aside here). This relationship is not perfect since, for two identical cars, the degree to and manner in which they are driven and maintained will impact the value, and the cars may differ considerably in value 10 years after their contemporaneous purchase. Nonetheless, the general association can be described as an inverse one.
In many cases, such a relationship can be captured meaningfully by a correlation coefficient. These coefficients range from −1 to +1 (typically written as just 1, without the + sign). A value of −1 represents a perfect...