The head of institutional research at a university believed that the mean age of full-time students was declining. In 1995, the mean age of a full-time student was known to be 27.4 years. After looking at the enrollment records of all 4934 full-time students in the current semester, he found that the mean age was 27.1 years, with a standard deviation of 7.3 years. He conducted a hypothesis of H0: µ = 27.4 years versus H1: µ < 27.4 years and obtained a P-value of 0.0019. He concluded that the mean age of full-time students did decline. Is there anything wrong with his research?
Answer to relevant QuestionsExplain the difference between statistical signiﬁcance and practical significance. A simple random sample of size n = 65 is drawn from a population. The sample mean is found to be 583.1, and the sample standard deviation is found to be 114.9. Is the population mean different from 600 at the α = 0.1 level ...The manufacturer of a toner cartridge claims the mean number of printouts is 10,000 for each cartridge. A consumer advocate is concerned that the actual mean number of printouts is lower. He selects a random sample of 14 ...Assume that the populations are normally distributed and that independent sampling occurred. (a) Test the hypothesis that µ1 ≠ µ2 at the α = 0.1 level of signiﬁcance for the given sample data. (b) Construct a 90% ...Construct and interpret a 95% conﬁdence interval about µM - µW using the data from Problem 8. How might a marketing executive with McDonald’s use this information?
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