Thread: basic statistics; conducting a z-Test

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??


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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 of 36 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 who did not see the film is 75. The standard 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?

1. What does it mean to set alpha at .05?
2. What is your null hypothesis? Alternate hypothesis?
3. Is this a one-tailed or two-tailed hypothesis?
4. What is the criterion z?
   Suppose the obtained z was -2.5. Do you reject or fail to reject the null hypothesis?
5. State in words what you have found.

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


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


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

Hey stacyxoxo.

Can you show us an attempt at the questions? If you make a partial attempt, then we can add to it in a constructive manner.

hi chiro

i attached pictures of my work to the original post. i hope that will do, its hard typing out the work on a computer