am i looking for average here

I have a note field that I'm trying to determine a cut off length to display.

I have some numbers

Note Length and # of Notes with that le开发者_开发知识库ngth

How do I come up with a good average? Do I need more information?

Thanks, rod.

Are you trying to do this dynamically? Usually these kinds of decisions are driven more by UI/usability concerns, than average length of data.

E.g., for a note preview in a tooltip or table, I might choose to use a max of 50 characters, even though a note might be as big as 4,000 characters.

I wouldn't use an average, I would do a distribution graph first and find out the distribution of values..and then adjust the percentage cut-off to whatever goals you are trying to accomplish.

An average can be really skewed by a few outlying lengths. You may find out, for example, that 95% of your notes are under xxx length, and if you can live with xxx, then 95% of your notes will be fully displayed.

Two thoughts:

1. If the maximum length isn't too bad, just use maximum.
2. If you're going to do the average, you might want to eliminate the items that are one or two standard deviations out. A couple really long (or really short) notes can really skew your average.

The Average (Arithmetic Mean) would be (Note Length * # Notes with length) / Total # notes of all lengths