Question 2: Upon what assumptions does their calculation of the normal range depend? Do you think that these assumptions are met?
There are two assumptions: for any normal range, data should be from a representative sample of the normal population, and to use their method of calculation the measurement should follow an approximately Normal distribution.
Whether staff and visitors to the hospital are a representative sample is difficult to say. They have been careful to exclude people who might possible be pyrexic, which looks sensible.
The histogram suggests that the fit to the Normal distribution is good, even in the tails, so their calculation would be appropriate. The sample is large, too, so the limits should be well estimated.
Back to question.
This page maintained by Martin Bland.
Last updated: 2 March, 2007.