PPT Slide
An investigator developed the idea that an excess of a particular chemical (RTQX) in the brain during infancy produced permanent mental retardation. To gather evidence for this notion, he used 30 infant rats and their mothers in an experiment. The rats (infants and mothers) were assigned to two groups of 15 infant-mother combinations on a random basis. In one group, the C Group, the infants were nursed by the mother rats. In the other group, the E Group, infant rats were kept separated from their mothers and fed by bottle. The chemical RTQX was mixed with the milk in the nursing bottle. Tests of mental development were made on both groups at various points in time, even far beyond the nursing period. At every point of the testing the infant rats in the E Group were found to be inferior to those in the C Group. The experimenter concluded that the chemical RTQX causes mental retardation.
.What is the independent variable?
What is the dependent variable?
.Is this a true experiment or a descriptive study? Why?
.Do you agree with the experimenter’s conclusion? Why?