Variation is a concept that is based more on the concept of ratio. In general, variation implies change in any condition or level or amount or limits for any given quantities. For example, we say that as labor increases, the wages increases. So there is difference in wages with a minor change in labor even. For if labor increases wages to be paid will increase and if labor will decrease so will be wages. Also if labor increases, time taken will be less and if it decreases, time taken will be more. There are examples of direct and inverse proportion respectively. There are many types of variation depending upon various factors like direct and inverse variation or combined variation, joint variation.