An increasing degree of control is needed as studies move from descriptive or correlational to experimental designs. which of the following is true about control?
a. the degree of control will not influence the results of descriptive or correlational studies.
b. sample selection is not included as part of the control in a research study
c. control is needed to reduce the effects of confounding or extraneous variables on the variables being studied.
d. increasing control and rigor in a study ensures that outcomes will be as the researcher predicts