Is it important that the experimental group and control group differ in only one way in an experiment?

No. In fact most real experiments vary a number of different parameters. This is perfectly fine as long as you have multiple samples or do multiple experiments. In fact if you do an experiment that only varies one parameter then you stand a good chance of missing some important science.





Imagine a chemistry experiment where you are mixing three chemicals together and you want to find the best concentrations to use. If you pick some concentration for chemicals A and B, and then vary the concentration for C you will get some answer that depends only on Chemical C. But instead if you vary the concentrations of chemicals A,B,and C then your answer will be much more complete. Then you could try changing the temperature, pressure, etc.Is it important that the experimental group and control group differ in only one way in an experiment?
yes it is very important! the experimental group should only have one variable because then you won't have too many variables to work with! if you have too many, it's hard to tell what caused the change in the experimental group.Is it important that the experimental group and control group differ in only one way in an experiment?
yes that way you can prove that other factors that were different didn't scew your results