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 0.0020. he concluded that the mean age of full-time students did decline. is there anything wrong with his research? a. no, the hypothesis test was conducted correctly, and the correct conclusion was made. b. yes, a p-value only indicates the likelihood of getting a result as extreme or more extreme as the one found, the head of institutional research needs to include a confidence level. c. yes, the head of institutional research has access to the entire population, inference is unnecessary. he can say with 100% confidence that the mean age has decreased. d. yes, the head of institutional research stated the hypotheses incorrectly; a left-tailed hypothesis test was conducted instead of a two-tailed test.