The head of the insitutional reasech at a university believe

The head of the insitutional reasech 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 u=27.4 years vs. H₁ u<27.4 years and obtained a P-Value of 0.0020. He conluded that the mean age of full time students did decline. Is there anything wrong with his reaseach?

1. Yes, the head reasech has access to the entire population, inference in unnecessary. He can say with 100% confidence that the mean age has decreased.

2. Yes, a P value only indicated the likeihood of getting result as extremem or more extreme as the one found, the head reaesch needs to included confidence level.

3. Yes the head stated hypothes incorrectly; a left tailed hypothesis test was conducted instead of two tailed test

4. No, the hypthes test was conducted correctly, and the correct conclusion was made.

Solution

3. Yes the head stated hypothes incorrectly; a left tailed hypothesis test was conducted instead of two tailed test