An experimental group is the group in an experiment that receives the variable being tested. One variable is tested at a time. The experimental group is compared to a control group, which does not receive the test variable. In this way, experimental groups are used to find answers in an experiment.
1 At around 9 months of age, babies begin to pull themselves up to a standing position. 2  By 10 months of age, a baby should be able to grasp objects with thumb and forefinger.
Conveniently, this is about the distance between a mother and baby's face during feeding, making it a great time for getting to know each other. As for the age-old question of how colorful a newborn's world is, we now know that babies can see color right from the start if the color is very bright. Is My Baby's Vision Normal? A great test of vision is just having some up-close and personal time with your baby, who by 4 to 6 weeks of age should be gazing intently into your eyes and mimicking your facial expressions.