Is it possible to calculate median value and interquatile range for a set of numbers containing a range or inequalities? I am trying to make simple median and IQR calculations that involve numbers (in  percentages) appearing in a range and inequalities in addition to whole numbers. My sample dataset looks like this:
5, 10, < 1, 10 - 20, 25, > 90
Any suggestions on how I can perform these two calculations on such a dataset?

If you only had "< 1" occuring you could compute the median.  In general you can't estimate what you want unless you assume a smooth parametric distribution and explicitly handle left, right, and interval censoring in computing the likelihood function so that you can get maximum likelihood estimates of the parameters of that distribution.  Then you compute the mean and quantiles which are functions of those underlying parameters.  It's pretty involved.
