07-11-2018, 07:56 PM
(07-11-2018, 07:46 PM)fredtoast Wrote: No it doesn't
https://answers.yahoo.com/question/index?qid=20070823110409AAaQk6o
Yahoo answers? For real. Did you feel kinda silly when you linked it?
TL;DR (Too Long; Didn't Read)
Testing only one variable at a time lets you analyze the results of your experiment to see how much a single change affected the result. If you're testing two variables at a time, you won't be able to tell which variable was responsible for the result.