Answer to Question 1
By assigning participants to groups on the basis of the flip of a coin, numbers drawn from a hat, or a table of random numbers, the chance is increased that characteristics other than the independent variable will be equally distributed across treatment groups.
Answer to Question 2
The rate and expression of childhood symptoms and disorders often vary in relation to demographic and situational factors, such as socioeconomic status (SES) (e.g., the social, economic, and physical environment in which the child lives as reflected in measures such as family income, education, or occupation); parents' marital status; and the child's age, gender, and cultural background, to name but a few. Consequently, these variables must be assessed and controlled in most studies.
The Trundholm Sun chariot pulled by a horse is a sculpture believed to be illustrating an important
This young child is pulling at the ear and acting fussy, two important signs of otitis media.
Overview of a computer-controlled high-pressure common rail V-8 diesel engine.
Hydrolysis reactions for some biochemically important phosphate compounds (part 1)
Healthy Eating Behaviors and Weight Gain Are Important Considerations during the Third Trimester
Some human traits controlled by a single gene