Hi,
I've gone through the first paragraph for you and highlighted problems in the rest. Your main difficulty seems to be the use of singular/plural, verb tenses and knowing when you need a determiner. There are other errors as well though. Once again, NO CAPITAL LETTER AFTER COMMAS! Nicely planned essay. Sender/receiver not the right choice of words. You might want to find an alternative to 'set agenda' as well.
The hidden role of mass media
Many people think that the mass media has two roles, that is, for entertainment and for information. .In fact, the mass media has a hidden role; agenda setting. Agenda setting is controlling what news can or can’t be released . Agenda setting has three factors, that is, media policy, media type and government policy. Firstly, media policy has a role in agenda setting, for instance, if that newspaper is a sport newspaper and it has two stories, one about the football league and one about the World Bank, then they will put the football story on the front page and wouldn't use the World Bank story. In additional, the editor may use agenda setting for the newspaper's image.If that newspaper is a 'hard news' newspaper, they must put any news on the front page that is compatible with their policy. If they put odd news on the front page that may degrade their image.
Next is media type. Much of the mass media chooses news or message that compatible their type and receiver. If the sender want to send message about anatomy to well educate people, The sender may send in feature or article form. On the contrary ,if the massage want to send in feature or article form and receiver is child or teen , The sender must send via another form. For example, when I was child I have seen cartoon about anatomy . If mass media isn’t choose message or news in right way and right form that message may be lack of effective message.
Last, about government policy. Government policy is greatest factor to be made up agenda setting of mass media. In Many country, the governments can control mass media via law and policy by prohibit something that may can country to unstable status. In addition, the dictatorial leader use mass media for propaganda that can convert people attitude. In the same way the democratic government may control people via news. If the news has effect with cabinet in that country, they may bribe news station by broadcast news that can improve their image or distort news in other way.
All above factor that made up agenda setting, that effect public opinion. If many mass media have policy about war in Lebanon that isn’t important news and put that news in small section. People may think about war in Lebanon is unimportant event or ordinarily events. Moreover, agenda setting can change attitudes about exalted person by report bad news about that person only. That may change attitude about that person. In advertiser, many brands put brand ‘s product in many way, especially in film and cartoon that can set agenda in receiver mind “ everyone use it “ or “ do you want to outdate? “. In the same way , mass media can change social value by put “ everyone use it “ or “ everyone do it “ in public mind, for example, if media want to change attitude about wars ‘cause some people think war is commonly events in the world. The media may broadcast about effect of war in many ways. Finally, agenda setting is used in many way but base on one purpose “ persuade receiver’s mind “.