R VALUE

1 The correlation coefficient, r, is a measure of the closeness of the relationship between two variables. These are not independent and dependent variables , but just two variables that happen to exist in the same time or place. An example would be examining the correlation between the density of plants in a plot and the heights of the plants. The value of r can range from -1 to +1. As r approaches +1 the more positive the relationship. An r-value close to zero indicates no relationship and r-values below zero indicate a negative relationship.

2 R-value is a term predominantly used in the building industry to rate the insulative properties of construction materials and building assemblies.

It is derived from the U-factor (see below). The higher the R-value, the greater insulation value.