what is a dependent variable

In an equation such as  y  = 2x + 1,  

the x is the "independent" variable because you can enter any number for x,

while the y is the "dependent" variable because its value is dependent upon the number that you entered for x.

In an experiment, such as determining how many calories that you burn per hour of one particular type of exercise,

the numer of hours that you exercise is the independent variable,

while the number of calories burned is the dependent variable. 

If you work for a wage, the number of hours worked is the independent variable while the amount earned is the dependent wage.

the factor you obsereve or measure during an experiment.