Report on Bowling for Columbine

I've studied this documentary to look at how bias is used in documentaries as a convention.
Bias through selection and omission was used by them showing a clip of Michael Moore bending down to Charlton Heston's intercom, this proves that Charlton Heston is too important to see without asking and he is a big man, (he is made inferior). The music is from roundabout 1940's, it is a jolly, jazz piece. It is a piece of 'black' music and this created irony when becomes evident to Charlton Heston as a racist.
Bias through placement was used for Charlton Heston's posters behind him; they make him look glorious and a hero. His employees clearly put them there because they want people to think certain things through positive connotations.
Bias by headline/title was used by Michael Moore saying that he is a member of the NRA (American Gun Club) and that is the reason why Charlton Heston agrees to see him.
Bias through choice of words by interviews, Michael Moore used a lot of open/closed questions.
Bias by captions, photos, edits, lighting and camera angles was used by cutting out the rubbish and keeping the good, so it makes it go question...answer, alternatively. He also shows Charlton Heston the photo of the 6 year old girl that was shot and killed by another 6 year old. He came with this photo, knowing that the interview would get out of hand. The documentary was edited well and if you aren't expecting edits, you can't notice it at all. Statistics were used a lot, they are the truth and they are a good way to be bias because the person that they are aimed at, cannot argue back and it made Charlton Heston angry. Statistics are powerful and you cannot argue back because you know that they are the truth.
Leading questions work in the way that you have already decided what you are going to talk about and you know where it will lead to.