It's important that researchers choose the best type of design experiment in order to have reliable and valid results. There are multiple methods to test and the number of variables can determine which one should be used. Two of these available designs are two-group and factorial (Myers, & Hansen, 2012). The two group would be the best choice when researchers want to only manipulate one variable and factorial would use when an experiment will be manipulating multiple variables(Myers, & Hansen, 2012). Each design can be effective in both cases and it's important that the best design is chosen to either support or disprove the hypothesis being tested.