Question 763137
1)  First, the difference between the results of the experiment and the null hypothesis is determined.  The probability of a difference that large or larger is computed. This probability is compared to the significance level. If the probability is less than or equal to the significance level, then the null hypothesis is rejected and the outcome is said to be statistically significant.
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2)  Our Null hypothesis is "The mean score on the questionnaire of the group watching the film is statistically equal to the mean score for the group that did not watch the movie".  The Alternate Hypothesis is "Watching a film on institutionalization will change students’ attitudes about chronically mentally ill patients, that is, the mean score for the group watching the film will be statistically different from the mean score for the group that did not watch the film".
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3)  This is a two-tailed hypothesis , since the researcher hypothesizes that the film will change students attitudes.
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4)  The criterion z for alpha = .05 are -1.96 and +1.96.  We reject the null hypothesis if z < -1.96 or z > +1.96
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5)  We reject the null hypothesis for z = -2.5
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6)  There is a statistical difference between the mean scores of the two groups which implies that the film did change students’ attitudes towards the chronically mentally ill.
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