[R] Percent Change After Each Interval
Jia Ying Mei
jiamei at Princeton.EDU
Wed Jul 30 17:18:45 CEST 2008
Hi,
I have a data set (attached, and which I've asked about before)
containing countries, prices and dates. I am trying to find the mean and
median (by country) percentage change of each price change. For example:
Date Australia
6/30/07 2
3/31/07 2
11/30/06 2
5/2/06 2
1/11/06 2
8/5/05 2
7/31/05 2
4/30/05 1.5
1/31/05 1.5
1/3/05 1.5
1/2/05 4
So for this period for Australia, there are 2 price changes. The first
change is a 25% change, and the second is 266.66%. If this were all the
data there was, the mean percentage change is ~146% and the median would
be the same.
I was wondering if anyone knew a way that would collect the percentage
change at each price change and then calculate the mean and median of
those percentages, and could do this for a data set with a lot of
countries (so the output would be broken up by country).
Any help would be appreciated! Thanks!
Jia Ying Mei
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