R help - Jul 2009 - assessing data variation

I have data like so:

time	datum
30	12
60	24
90	37
120	41
150	8

In addition to standard deviation, I want to measure the average of
the differences in data for each time interval, i.e. average of 24-12,
37-24, 41-37, 8-41. Is there a statistical term for this task? Which
package should I use please?

rhelp at conference.jabber.org

On 7/10/2009 5:21 AM, e-letter wrote:
> I have data like so:
> 
> time	datum
> 30	12
> 60	24
> 90	37
> 120	41
> 150	8
> 
> In addition to standard deviation, I want to measure the average of
> the differences in data for each time interval, i.e. average of 24-12,
> 37-24, 41-37, 8-41. Is there a statistical term for this task? Which
> package should I use please?
  I don't know a term for it, but you might try something like this:

mydf <- data.frame(time = c(30,60,90,120,150),
                   datum = c(12,24,37,41,8))

diff(mydf$datum)
[1]  12  13   4 -33

mean(abs(diff(mydf$datum)))
[1] 15.5

?diff
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