I have this income distribution data for various groups: https://docs.google.com/spreadsheet/ccc?key=0Akwg3n_e05cCdEdtT0VZYU5keW5DVkNoNmpBWmdzeUE
As you can see, I have intervals/bins with varying widths. I also have an open-ended interval and the mean income in that open interval varies a lot between groups.
For pedagogical purposes, I'd like to be able to calculate how many people and/or percent is in a given interval, given an equal bin width.
On an x-axis from 0-2000 with a bin width of 10, I'd like to be able to say how many people is in the 590-600 group.
1) Is this doable?
2) Do I need to fit a distribution to a histogram or how do I do it?
2b) What would you base this histogram / distribution on (mean, median etc.)? (As mentioned, the mean in the open-ended interval varies a lot between groups, something I'd like to take into consideration = show truthfully graphically.)
3) Can you please explain this in simple mathematical operations based on the data given?