Investigators interested in the effects of nutrition on wound healing randomly assigned patients recovering from burn injuries to two groups. One group received protein supplements and the second group did not. The random assignment was used to:
A. eliminate the systematic influence of any other variable.
B. provide a control for earlier nutritional status.
C. make the groups equal in terms of the dependent variable.
D. obtain groups equal in number.
Question 2
There are several ways in which confounding extraneous variables can be controlled. Which control technique is considered the best?
A. matching
B. random assignment
C. counterbalancing
D. selection
Effects of growth rate on development.
Field experiment on effects of predation on male guppy colouration
Pneumothorax; A, penetrating wound; B, ruptured bleb on the lung.
Fires Commonly Are Major Secondary Effects
Effects of Therapy for Stuttering A functional MRI scan shows regions of the superior temporal lobe
Growth of cultured cells from patients with xeroderma pigmentosum (XP)