Date:         Fri, 1 Sep 2006 11:31:23 +0200
Reply-To:     Spousta Jan <JSpousta@CSAS.CZ>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Spousta Jan <JSpousta@CSAS.CZ>
Subject:      Re: change of perceptions
Comments: To: DR VEENA Joshi <drveena.joshi@gmail.com>
Content-Type: text/plain; charset="us-ascii"

Hi Veena,

1) It is possible that there is no clear "turning point" - rather, the
changes may be continuous, eg. every year of age may change the
perception by 0.01 p. Try to plot the means of the Likert scale against
the age groups say 10 years wide and look for possible turning points.

2) An useful method for detecting breakpoints of this type are decision
trees - run a tree (C5, CART, CHAID or whatever you like) with the
likert scale as dependent/target variable and age as the predictor.

HTH

Jan


-----Original Message-----
From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU] On Behalf Of
DR VEENA Joshi
Sent: Friday, September 01, 2006 11:22 AM
To: SPSSX-L@LISTSERV.UGA.EDU
Subject: change of perceptions

Hi,

We have done a survey on perceptions about healthcare system using
likert scale (1 to 5). One of the demographic variable is age which is
continuous.
I categorized age into 3 groups <40, 40 - 60 and >60 and found that
respondents perceptions/attitude differ age groupwise.
I would like to find the truning point at which the difference exists.
How do I get this?

I am trying to get small age groups say 5 years, but the age ranges from
18 to 90 years.


pl. advice.

veena