Levels or Independent Variables in ANOVA

There are four different types of mobile phones (same brand) that are used as stimuli in an experiment.

• In the first example, if "mobile phone" is the independent variable in the study, which one of the two is appropriate? (i) mobile phone is the independent variable with four levels or (ii) this study has 4 independent variables (since there are 4 different mobile phones)

The same webpage is modified into two versions: one with a blue background, and the other version with an orange background.

• In the second example, if webpage is the independent variable, can we say that the study has one independent variable with 2 levels or does it have two independent variables?

Kindly clarify.

• Is this a homework problem? Apr 15, 2014 at 1:09
• Why? I am trying to understand the concept Apr 15, 2014 at 1:26
• Ask yourself this, "if each phone is a separate variable, then in what what is it varying?"
– John
Apr 15, 2014 at 4:45
• so it will be one independent variable (mobile phone) with four levels (types of mobile phones). May 30, 2014 at 18:11

Since this can be a confusing issue for new statistics students, I will direct you to the following link which talks about independent variables and levels. Hopefully this helps you answer the question. As they note on this site regarding variables:

"Variables are properties or characteristics of some event, object, or person that can take on different values or amounts (as opposed to constants such as $π$ that do not vary). When conducting research, experimenters often manipulate variables. For example, an experimenter might compare the effectiveness of four types of antidepressants. In this case, the variable is "type of antidepressant"."