one
one
It can have as many as it needs. You can even change different variables at the same time and study their individual influence with proper statistical tools in many type of experiments.
In a properly designed experiment, it is important to have at least 2 controlled variables. With two variables you are able to remove one at a time and see the effect in your setup.
There are many different kinds of controlled experiments. Most controlled experiments have many components that can be kept in check.
To test the theory thoroughly, many controlled experiments were done.
1) I learned that you can have as many variables as you want. 2) You can change the variables. 3) Variables is used in an experiment. 4) A variable is something that can be changed, such as a characteristic or value. Variables are generally used in Psychology experiments to determine if changes to one thing result in changes to another.
You can only change ONE at a time. That's what makes it controlled. It's the only sure way to know what actually changed the experiment.
As many as you need. You can't change more than one if you want accurate results.
Scientists perform controlled experiments in order to reduce as many third variables as possible. This means they are trying to prevent variables not directly related to the study from influencing the results.
There are three types of variables tested: manipulated variables, controlled variables, and experimental variables.
it is difficult to control all variables except the one being tested
An experiment of any kind can have infinitely many variables. A controlled experiment can have just as many, provided that all but one are kept exactly the same.