hi everyone

i'm new here so i don't know how this works so i'll just ask my question and hope someone can help me i have a quiz coming this friday and my professor gave us this really confusing practice worksheet for practice but i don't understand any of it. we just started school and he gives us this??

---------------------------------------------------------------------------------------------------

Quiz Practice: Conducting a z-Test

A researcher predicts that watching a film on institutionalization will change students’ attitudes about chronically mentally ill patients. The researcher randomly selects a class of36 students, shows them the film, and gives them a questionnaire about their attitudes.The mean score on the questionnaire for these 36 students is 70. The score for a similar class of students whodid not see the film is 75. Thestandard deviation is 12.Using the five steps of hypothesis testing and the 5% significance level (i.e. alpha = .05), does showing the film change students’ attitudes towards the chronically mentally ill?

- What does it mean to set alpha at .05?
- What is your null hypothesis? Alternate hypothesis?
- Is this a one-tailed or two-tailed hypothesis?
- What is the criterion z?

Suppose the obtained z was -2.5. Do you reject or fail to reject the null hypothesis?- State in words what you have found.

i'm really confused? if anyone could explain this stuff to me i'd really appreciate it

Quiz 1 is 25 January 2013, no makeups allowed, so don't be late!!

---------------------------------------------------------------------------------------------------

edit:

its kinda hard typing out the work for this problem so I attached pictures of the work i've already done, its sort of complete but I am unsure of myself. so any input would be greatly appreciated