How long has she been like this? How old are the other children, and are you all the same family, or are there step-children, change of partner, new house, or whatever?
It doesn't take much to unsettle children, or make them feel vulnerable, and that they aren't in a position to control what happens in their life. So, as they see it, the only 'weapon' they have is having a tantrum.
I always say to parents, usually with younger children, to try and have a calm, quiet environment. When our DS was young we never had the TV or radio on, except when we specially wanted to watch or hear the programme. I may be the only person in the world who thinks this, but I have always believed that the continuous background noise that seems to take place in many homes, contributes to children's inability to listen, concentrate and learn in school.
I worked in primary schools for over twenty years, and invariably children don't really WANT to be naughty and get told off all the time, but something in their lives has sent them down that route.
What is she like at school, both behaviour and work-wise? Has she been worse over Christmas, as that can be a stressful time even for well-settled families?
If you can answer some of these queries, I'll see if I can shed any more light on the problem.