From Wikipedia, the free encyclopedia. Phototoxicity, also called photoirritation, is a chemically induced skin irritation, requiring light, that does not involve the immune system. It is a type of photosensitivity. The skin response resembles an exaggerated sunburn.
Contribution margin ratio measures the percentage of sales that would increase net income. To calculate it, divide contribution margin by sales, either in total or per unit: Suppose a gadget selling for $100 per unit brings in $40 per unit of contribution margin.
DEFINITION of 'Dependency Ratio'. A measure showing the number of dependents (aged 0-14 and over the age of 65) to the total population (aged 15-64). Also referred to as the total dependency ratio. Calculated by: