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.
Dr. Goei explains that a newborn infant usually sees very high-contrast shapes and movement and color such as black, white, and red, she says. When the majority of babies are born, their eyes move in different directions, Dr. Goei says. By 3 to 6 months of age, babies are using their eyes together very nicely. If the eyes seem to cross all the time, that's not normal. It should be very apparent that the child can use both eyes simultaneously..