In an experiment to see if the comfort of chairs in a classroom makes a difference in how long students will work on math problems, one group was in standard chairs, and one group was in padded, comfortable chairs. What is the dependent variable in this experiment?

The dependent in this case would be the type/quality of chairs as that is what you are changing.

Answer: How long students will work on math problems.

Explanation:

An independent variable is the one which can be altered in an experiment. This variable can be regulated, changed and manipulated by the experimenter or researcher so as to determine it's influence over the dependent variable. The dependent variable is the variable which is not required to be manipulated manually instead the changes occurring in the variable is because of the changes occurring in the independent variable. The dependent variable is also called as the experimental variable or test variable. The dependent variable is the considered so as to determine the result of the experiment.

In the given situation, how long students will work on math problems is the outcome of the experiment. This is based upon two types of chairs that are the standard and padded comfortable chairs. The two types of chairs are the independent variables. The affect of these chairs over the work duration is the dependent variable.

Thus, How long students will work on math problems. is the dependent variable of the experiment.