Answer:

1.You can think of independent and dependent variables in terms of cause and effect: an independent variable is the variable you think is the cause, while a dependent variable is the effect

2.Dependent and independent variables are variables in mathematical modeling, statistical modeling and experimental sciences

3.Inference is just a big word that means a conclusion or judgement.  If you infer that something has happened, you do not see, hear, feel, smell, or taste the actual event.  But from what you know, it makes sense to think that it has happened.  You make inferences everyday.  Most of the time you do so without thinking about it.  Suppose you are sitting in your car stopped at a red signal light.