Give an example of an experiment where a control group would not be necessary.

DoE studies, for example do not require control group, since they usually involve models in which the number of variables are substantially smaller than the  number of experiments. The DoE analysis provides a description model that shows how the responses or output variables  depend on the factor settings or input variables. As long as the unknowns are substantially less than the number of equations, there is very minimal risk of over-fitting.

4/6 = 2/3

so it should take 3/3 hours per man. so 9 hours is the answer 3*3 =9

step-by-step explanation:

so far i think you have the right thing going for you just remember soh cah toh

step-by-step explanation:

sine over hypotenuse

cosine   equals adjacent

tangent over hypotenuse