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.
Between the ages of 0-3 months, your baby will: 1  See clearly within 13 inches from her face. 2  Be comforted by a familiar adult. 3  Respond positively to touch. 4  Quiet when picked up. 5  Listen to voices. 6  Smile and show pleasure in response to social stimulation.