```Date: Thu, 25 Sep 2003 12:00:57 -0400 Reply-To: "G. David Garson" Sender: "SPSSX(r) Discussion" From: "G. David Garson" Subject: Re: Correlation In-Reply-To: <5.1.0.14.0.20030925111043.0248ac78@poste.umontreal.ca> Content-type: text/plain; charset=ISO-8859-1 Pearson's r for a dichotomy and continuous variable is the same as point-biserial correlation, which is recommended for this purpose, so in one sense it is true that a dichotomous or dummy variable can be used "like a continuous variable" in ordinary Pearsonian correlation. However, when the continuous variable is ordered perfectly from low to high, then even when the dichotomy is also ordered as perfectly as possible to match low to high, r will be less than 1.0 and therefore resulting r's must be interpreted accordingly. Unequal splits in the dichotomy and curvilinearity in the continuous variable will both further depress the maximum possible correlation even under perfect ordering. Moreover, if the dichotomy represents a true underlying continuum, one would have attenuated correlation. Date sent: Thu, 25 Sep 2003 11:20:02 -0400 Send reply to: Charles-Édouard Giguère From: Charles-Édouard Giguère Subject: Re: Correlation To: SPSSX-L@LISTSERV.UGA.EDU > If it's a yes/no variable (dummy variable), I think you can use it as if it > was a > continuous variable. Otherwise you can consider the non-parametric correlation. > > the syntax is : > nonpar corr var=var1 with var2. > > Charles-Édouard. > > At 10:58 2003-09-25, Cathy Smith wrote: > >Dear All, > > > >Pardon my simple question. I have to variables. One is categorical [1,0] and > >the other is continuous. I would like to find the correlation between the > >two. Were both variables continuos, I would have done it using the Correlate > >button in SPSS. Since one is categorical, am not sure how to do it. Please > >help. > > > >Cathy Smith. > > > >_________________________________________________________________ > >Instant message in style with MSN Messenger 6.0. Download it now FREE! > >http://msnmessenger-download.com > ____________________________________ G. David Garson Editor, Social Science Computer Review NCSU Box 8102 Department of Political Science and Public Administration North Carolina State University Raleigh, NC 27695-8102 For UPS and Express Mail: G. David Garson 212 Caldwell Hall / PSPA Hillsborough Street North Carolina State University Raleigh, NC 27695-8102 Tel. 919-515-3067 Fax 919-515-7333 E-mail: David_Garson@ncsu.edu __________________________________________________________ G. David Garson Editor, Social Science Computer Review NCSU Box 8102 Full Professor, Department of Political Raleigh, NC 27695-8102 Science & Public Administration, NCSU Express Mail, add: Tel. 919-515-3067 106 Caldwell (PSPA) Fax 919-515-7333 or 7856 Hillsborough St. E-mail: David_Garson@ncsu.edu ```

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