application or intradermal injection of a substance to the skin to test the body's reaction to it. Such a test detects an animal's sensitivity to such allergens as dust and pollen, or to preparations of microorganisms believed to be the cause of a disorder.
A direct relationship graph is a graph where one variable either increases or decreases along with the other. The general equation for a direct relationship graph is y = mx + b, where y denotes the...
A relationship between two variables can be described by an equation or a formula. This relationship can be linear, quadratic, square root, or almost any other type of function you can think of. We will focus here on a linear relationship between two variables where one is a constant multiple of the other. This is a special relationship called direct variation. In general, we say that y varies directly as x if there is a constant k so that the equation is true. When graphed, the constant k will be the slope of the line, y = mx + b.