SPSS q-q plot to compare two distributions (any 2 distributions)

[Amy Klein]

I need to produce qq plots that compare two distributions – regardless of
what the distributions are.  For example, if I have 2 samples of a measure
A, and I want to compare if A's distribution in sample 1 is the same as the
distribution of A in sample 2, how can I do this by producing a q-q plot
that plots the qantiles (of A) from sample 1 against the quantiles (of A)
from sample 2? (I know how to compare the two distributions using K-S, but I
need the q-q plot).  Please let me know what syntax I can use or refer me to
where I can learn it.  Thanks

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[Arthur Burke]

Why not use side-by-side boxplots?

Art
_____________________________________________
Art Burke
Northwest Regional Educational Laboratory
101 SW Main St, Suite 500
Portland, OR 97204-3213



-----Original Message-----
From: Amy Klein [mailto:[hidden email]]
Sent: Friday, January 09, 2009 11:42 AM
To: [hidden email]
Subject: SPSS q-q plot to compare two distributions (any 2
distributions)

I need to produce qq plots that compare two distributions - regardless
of what the distributions are.  For example, if I have 2 samples of a
measure A, and I want to compare if A's distribution in sample 1 is the
same as the distribution of A in sample 2, how can I do this by
producing a q-q plot that plots the qantiles (of A) from sample 1
against the quantiles (of A) from sample 2? (I know how to compare the
two distributions using K-S, but I need the q-q plot).  Please let me
know what syntax I can use or refer me to where I can learn it.  Thanks

=======
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command SIGNOFF SPSSX-L For a list
of commands to manage subscriptions, send the command INFO REFCARD

=====================
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[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
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INFO REFCARD

[Arthur Burke]

qqplot in R does what Amy wants.

Art
-------------------
Art Burke
Northwest Regional Educational Laboratory
101 SW Main St, Suite 500
Portland, OR 97204-3213

-----Original Message-----
From: Amy Klein [mailto:[hidden email]]
Sent: Friday, January 09, 2009 11:42 AM
To: [hidden email]
Subject: SPSS q-q plot to compare two distributions (any 2
distributions)

I need to produce qq plots that compare two distributions - regardless
of what the distributions are.  For example, if I have 2 samples of a
measure A, and I want to compare if A's distribution in sample 1 is the
same as the distribution of A in sample 2, how can I do this by
producing a q-q plot that plots the qantiles (of A) from sample 1
against the quantiles (of A) from sample 2? (I know how to compare the
two distributions using K-S, but I need the q-q plot).  Please let me
know what syntax I can use or refer me to where I can learn it.  Thanks

=======
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command SIGNOFF SPSSX-L For a list
of commands to manage subscriptions, send the command INFO REFCARD

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
INFO REFCARD