Suppose one lives in a fairly wealthy Western nation where life expectancy follows a normal distribution with mean $\mu$ = 80 and standard deviation $\sigma$ = 15. One reads a report that claims that 10,000 subjects who took part in a national program for improving one's lifespan lived significantly longer (at the 0.05 level of significance) than the population as a whole. In order to determine if the improvement is of practical significance, one should:
A) find out the actual mean lifespan of the 10,000 subjects.
B) find out the actual P-value.
C) use a two-sided test rather than the one-sided test implied by the report.
D) run the national program a second time to see if similar results are obtained.

Question

Quizplus · Accepted Answer

To determine if the improvement in lifespan is of practical significance, one needs to know the actual mean lifespan of the 10,000 subjects who took part in the program. This will allow for a comparison with the general population's mean lifespan to assess the magnitude of the difference.

Suppose One Lives in a Fairly Wealthy Western Nation Where μ\muμ

Suppose One Lives in a Fairly Wealthy Western Nation Where $\mu$