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1. The Null Hypothesis 2. The Alternative Hypothesis 3. The Test Statistic 4. The Decision Rule 5. The Decision 6. The Conclusion

A study completed 20 years ago reported that the mean amount of time volunteered per month for American adults was 8.4 hours with a standard deviation of 4.05 hours. To investigate whether or not volunteerism has diminished over the 20 years, 80 American adults are randomly sampled at this time and their mean amount of time volunteered per month is 6.9 hours. If the population standard deviation is known to still be 4.05 hours, test at the 5% significant level whether there is evidence that the number of hours volunteered per month is less know than 20 years ago. (this is the only exercise that uses the z-version of the test.) Show all six steps