# 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?

## 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?

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