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A question was asked on SO, and I answered it to the best of my ability, it was a fairly detailed answer. I think it got moved to:

Computing average value, ignoring "outliers"

And in the process, my answer has vanished! It's a shame, because I just wasted 10-15 mins on that, and it has gone! Do answers not get moved over either? The answer has dissapeared from my profile as well!

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Hmm no, the question didn't moved there, or it would show up as being migrated from the original site. That's a new question, asked independently on Cross Validated. – Cody Gray May 16 '11 at 14:07
@Cody I guess the question, and my answer, were both deleted on SO then? Someone commented the original question it should be moved to stats. But I didn't think anyone could delete a question if it had an answer! – Tom May 16 '11 at 14:07
They can delete it if there's only one answer and it hasn't been upvoted yet. If you still have the link, we can try and get the post migrated then merged. – Grace Note May 16 '11 at 14:08
@Grace oh I guess that's what happened them, that's a rotten shame :( I do believe my answer had value. – Tom May 16 '11 at 14:09
Do you remember which question was? – kiamlaluno May 16 '11 at 14:10
I think this is the original link… – Tom May 16 '11 at 14:11
I went to go look for the question in the list of recently-deleted questions in the moderator tools. It turns out that's no longer there (or at least I can't find it). Good thing you had the original link. I suspected you didn't, or you'd have posted it in your question. – Cody Gray May 16 '11 at 14:13
@Cody thanks for looking all sorted now :) – Tom May 16 '11 at 14:14

The question wasn't migrated; the OP deleted it and reposted on stats. Here's your text to copy and paste there: will probably help you better with this, and give a more comprehensive answer. I'm not a mathematician, but I suspect there are multiple ways to solve this issue.

As a programmer this is how I would tackle the problem. I'm not skilled enough to tell you if this is sound, but for simple data it should be acceptable.

Depending on the type of data, it might be acceptable to have cut off amounts. You will probably want a rolling average (often used in stock markets) that takes the average price over the last n months, this helps negate the impact of inflation, and then have a $n cuttoff or a percentage based cutoff, that is, any value that deviates +-20% or +-$n of the rolling average will be ignored.

This would work quite well for relatively stable markets, if your entity exists in a volatile market that fluctuates wildly then you probably want to find a different approach.

You also need to seriously consider cutting data off, you mention granny's yard sale which is arguably a legitimate cut off, but you need to accept that you will probably be losing legitimate data points as well that could have a significant effect on your results.

But again, there will be multiple ways to achieve this.

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Thanks I posted it again now! – Tom May 16 '11 at 14:13

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