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.
1 Baby talk at 9 months. From 6-12 months babies start to understand words like 'bye-bye', especially if there's waving at the same time. They may also begin to use a wider range of consonant sounds and tones of voice.  Baby talk at 12 months.