Can I graph data as median values, with error bars showing the range?

Make a box-and-whiskers plot, showing median, 25th and 75th percentiles, and range for a set of values in one column.

In Prism 3, create a table with no X column and the Y columns formatted for single values, or in Prism 4, choose the "Box & whiskers" graph type under the "One grouping variable tab".

Enter the actual data into one or more column(s). If you'd prefer, you may enter the values for minimum, maximum, median, 25th percentile and 75th percentile. Enter these values in the first five rows of a column (in any order).

Prism 3 makes a column scatter graph by default. Change this to a box-and-whiskers plot by clicking "Change... Graph Type...". Prism 4 will make the box and whiskers automatically.