I have some info culled from international registries of non-US rehab

medicine clinical trials

one of the questions of interest is whether a trial included subjects

over a certain age (e.g., 65 or 85); note that I do NOT have info on

the inclusion/exclusion criteria

for most trials I have the total N, but not for all trials

for some trials I have the mean and SD (though for some I only have the

mean) or I have info that can be used to estimate these values (I am

using the formulae suggested in Wan, X, et al. (2014), “Estimating the

sample mean and standard deviation from the sample size, median, range

and/or interquartile range”, BMC Medical Research Methodology, 14: 135)

If I have the N, the mean and the SD AND if I can assume that the ages

are approximately normally distributed, then answering the over65 or

over85 question is easy. However, I am uncomfortable making this

assumption and I am looking for citations that provide guidance for

either (1) different distributions (esp skewed ones) and/or (2)

truncated distributions but where the truncation point is unknown. If I

could find such cites, I could do a sensitivity analysis re: the assumed

normal distribution answer

So, does any one know of any such citations or have other suggestions?

By the way, I know that I could do a bunch of simulations to get there

but I think this would be more expensive then my clients want to go.

I note that I have received a suggestion to look at pop data to see if

distributional info for the countries where the research is taking place

can help with the assumption of normality