The potassium content of foodstuffs is very variable...
There was a bit of a wind and it was blowing onshore, variable, but quite strong.
...a variable rate of interest.
Decisions could be made on the basis of price, delivery dates, after-sales service or any other variable...
Other variables in making forecasts for the industry include the weather and the general economic climate.
It is conventional to place the independent variable on the right-hand side of an equation.