i find alot of the time at this age screaming is down to frustration they are starting to be able to do things independently , walking etc but their minds develop faster than their bodies and most of the things they want to do they still can't physically do , does this make sense ? basically they get frustrated because they either can't do what they want or can't explain to you what they want , i think the best thing is probably distraction , ( a different toy , go for a walk etc ) if this fails toddlers hate being ignored , if she thinks screaming won't get your attention she should soon stop , hope this helps