A lot of children at this age behave like this, does she get enough positive attention as sometimes children act out to get more attention,as negative attention is better than none. Is she at home with you has she any siblings she could be trying to compete with? Get her onto a childs Multiple Vitamin with antioxidants B Complex Vit C as these have shown to be beneficial .Three year olds are like this , read stories to her and Make sure she gets plenty of activities with her Dad .