[R] How should I organize data to compare differences in matchedpairs?

[Thomas Levine]

By accident, I didn't send this to the list.


On Thu, 2008-01-24 at 17:54 -0500, Thomas Levine wrote:

> Oh, right, I don't need the differences. I only needed to get the
> differences before because I was doing them sloppily in a spreadsheet
> and needed to do a t-test manually because the program didn't have a
> function for one type of t-test. I shall do it this way then.
> 
> 
> 
> On Thu, 2008-01-24 at 12:05 -0700, Greg Snow wrote: 
> 
> > Here is how I would do it (there are multiple ways you could do it, so
> > there is not single "Right" answer):
> > 
> > Assign each person a unique identifier.
> > 
> > Put all the information from the questionaire along with the idenifier
> > and anything else that does not change between rounds (age, sex, height,
> > ...) into one data frame.  This df will have as many rows as you have
> > subjects.
> > 
> > The round information then goes into a second data frame with each round
> > being a row (each subject has multiple rows) and include the unique
> > identifier on each row for that person.
> > 
> > If you need information combined from both data frames, then use the
> > merge function to merge the 2 data frames (or subsets of them) together.
> > 
> > Advantages of this method include:
> > 
> > Uses data frames which most of the analysis functions expect.
> > Each piece of data is only entered once (other than the id)
> > 
> > Disadvantage:
> > 
> > Data is split between 2 objects.
> > 
> > 
> > Hope this helps,
> > 
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