Evaluating The Alpha Level Of Significance And Its Effect On Students ' Attitudes About Chronically Mentally Ill Patients
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Conducting a Z-Test
The level of significance, which is symbolically denoted by alpha (α), indicates the highest probability of rejecting a true null hypothesis. In this regard, setting alpha at 0.05 means that an outcome will be determined statistically significant if its probability of occurrence is less than 5 times out of 100. Statistically significance implies that the outcome observed is larger than would be expected if the outcome was a result of chance alone (Shaughnessy, Zechmeister & Zechmeister, 2012). Importantly, the alpha level facilitates hypothesis testing, which is a process for evaluating claims about the interest population. In the present case, a hypothesis test is conducted on a researcher’s claim that watching a film on institutionalization will change students’ attitudes about chronically mentally ill patients.
In this case, the traditional hypothesis testing method using the 5-steps is used. Specifically, the five steps comprise a statement of the hypotheses, specification of the study design, conducting the study and collecting data, evaluating the data, and summarizing the results (Bluman, 2012). The hypothesis statement includes the null and the alternative hypotheses. In specifying the study design, the appropriate statistical test is selected, as well as the level of significance (α). Further, in evaluating the study data, the statistical test is performed, which facilitates the decision on whether to reject or retain the null hypothesis.
The null hypothesis (H0) states that there is no difference between a parameter of interest and a specific value. In the current evaluation, the null hypothesis specification is H0: the students’ mean score on the questionnaire about their attitudes is ...
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... data is collected for the hypothesis test. A test statistic is calculated using the statistical test and a decision is made about the null hypothesis.
The current problem applied hypothesis testing on a researcher’s claim that watching a film on institutionalization will change students’ attitudes about chronically mentally ill patients. Since the claim did not specify the direction of the effect, a two-tailed hypothesis test is performed. The z test is chosen because the population standard deviation is known. Additionally, a significance level of 5% is used, which yields the upper and lower critical values as z = +1.96 and z = -1.96, respectively. The observed z value is -2.5, which is less than the lower critical value. This implies that the null hypothesis should be rejected. Therefore, the results indicate sufficient evidence to support the researcher’s claim.