do control groups remove confounding factors
While control groups can sometimes help decrease the effects that confounding factors (also known as confounding variable) have on data, they do not eliminate them.
For example, if you were looking at how a dietary supplement affects weight loss…
Confounding variables in this experiment are any other factor that would affect weight loss (such as the subject’s calorie intake, exercise levels, age, etc.)
Having a control group and a treatment group can help increase the validity of your data, however it will not eliminate any of the confounding variables.
Random assignment eliminates confounding variables. Control helps with comparison.