Hello-

This is not excel specific, but I don't know where else to ask.

I have a huge file that shows 2 date columns. One columns shows purchase
date and the other shows registration date. I have found out how many days
between the 2 dates, but:

I would like to show some kind of "meaningful" stats on these. (Maybe on a
pretty chart?)
Such as:
- The longest time to register
- The quickest time to register
- The average time to register
I can probably do all the above easily in excel, but I really need to
understand the data. Can I predict how long it will take the "average"
customer to register? I don't think "average" is an accurate reflection.
There are those who take forever to get around to registering and those few
really skew the data. Is there some formula to "drop" a certain percentage or
something? I don't believe standard deviation works here without first
manipulating the extremes.

I realize this is more a question about stats than excel, but when you tell
me the formula, I need to know how to graph it so it looks real pretty :-)

Thanks in advance,
P.S. If there is a good website to read up on predictions/stats, please
point the way. I need to understand the formula as well as know how to use it
in excel.