```Date: Fri, 16 Dec 2005 20:03:16 -0800 Reply-To: David L Cassell Sender: "SAS(r) Discussion" From: David L Cassell Subject: Re: Interpreting an intercept In-Reply-To: <200512162305.jBGL2d2p014958@mailgw.cc.uga.edu> Content-Type: text/plain; format=flowed deepstar@GMAIL.COM wrote: >I have been interpreting intercepts in the past without problems, but >now i'm facing a multiple regression analysis with columns like: > > b >Woman: -6.6 >Caucasian: 8.5 >Experienced: 11.4 > >Intercept/constant B = 5.5 > >The numbers show the impact the three top variables have on a dependent >variable (salary). How am I supposed to interpret the intercept here? I don't know whether the above accurately reflects what you are doing, or not. After all, you say your real results are columns LIKE what you show us. But I'll take a guess, based on what you showed us. So you have a dummy variable WOMAN which is 1 for women and 0 otherwise. You have a dummy variable CAUCASIAN which is 1 for gringos and 0 otherwise. You have a dummy variable EXPERIENCED which is 1 for k or more years working, and 0 otherwise. And you have an intercept. And nothing else. (This seems like a really over-simplified model, so I hope you are checking your regression diagnostics and making sure your real problem has a reasonable model.) This means that the intercept is not just an intercept. It is the value of your response when WOMAN=CAUCASIAN=EXPERIENCED=0 . So if you have inexperienced non-white male workers, this is your mean salary estimate for them, according to your model. HTH, David -- David L. Cassell mathematical statistician Design Pathways 3115 NW Norwood Pl. Corvallis OR 97330 _________________________________________________________________ On the road to retirement? Check out MSN Life Events for advice on how to get there! http://lifeevents.msn.com/category.aspx?cid=Retirement ```

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