While I've used the files listed below for a while, there well may be bugs hiding inside. Please email me and let me know if you find anything, or if you have suggestions for upgrades, or if you have a really good stock tip.
My usual disclaimer applies, to wit: if you really want to do data analysis or statistical stuff, Excel is by far NOT the tool for the job.
That never stops anyone :-) , so here goes
There are several useful worksheets at Oatbran
I took a couple of them and added some features, extended the ranges of valid data, and so on. These are downloadable here, at the following links (all are zipped files)
First, a histogram generator. You can select the bin width; it provides an "Under" and "Over" category if data fall outside the Max and Min range you select.
This one smooths your data by performing a weighted average over nearby samples.
boxcar and exponential tail averages
And here is a wacky way to plot a scatter-plot line whose color changes at specified values of the y-axis. It's an amazingly kludgy way to do things, but so far as I can tell there's no better non-macro choice in Excel (which is why we all should use GNUplot or something).
And finally, my own homegrown time-waster. I use it these days primarily to shoot down people who say "I can do [blah whatever] using Excel". To which I say, "Yeah, well, I did *this* but that doesn't mean you should!"
(Just make sure the "field" tab is in front and click the GO button :-) )