Hey curiousone.

With regards to the median, you just find the observation that corresponds to half the observations on one side and half on the other (when they are ranked in ascending order).

You have 20+30+45+60+48 or 203 observations which means you want 101 to the left and 101 to th right which means you want the 102nd observation and this in the 40-60 range somewhere. If you have the raw data, you get the actual value but other-wise you leave it at that.