Date: Wed, 3 Sep 2003 00:14:51 GMT
Reply-To: Greg D <Andrew-greg@JUNO.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Greg D <Andrew-greg@JUNO.COM>
Organization: EarthLink Inc. -- http://www.EarthLink.net
Subject: Re: a simple linear extrapolation
Be careful about calling somebody an economist. Now, I am personally a
2-handed economist: on one hand the answer is this, and on other hand the
answer could be that.
"Ian Whitlock" <WHITLOI1@WESTAT.COM> wrote in message
> A mathematician would say:
> For any two points (x1,y1) and (x2,y2) with x1 ^= x2, then
> for any third value x, (x,y) is point on the line passing
> through the given points if and only if
> y1-y2 y - y2
> ----- = ------
> x1-x2 x - x2
> A statistician would say that your sample isn't large enough.
> A physicist would say if x1=x2 then rotate the axes and go to the
> mathematician and rotate his answer.
> An engineer would say for year 4 the value is .467803
> A Republican politician would say this shows we need more money for
> military budget and a bigger tax cut.
> A Democratic politician would say George W made the data.
> So you see, we will have to know your occupation before a definitive
> answer can be made. Are you an economist by any chance?
> -----Original Message-----
> From: Zhang, Jianying [mailto:Jianying.Zhang@UMASSMED.EDU]
> Sent: Tuesday, August 19, 2003 10:38 AM
> To: SAS-L@LISTSERV.UGA.EDU
> Subject: a simple linear extrapolation
> Hi, Dear SAS_L:
> I have completely forgotten how to do a simple linear extrapolation.
> I have three data points and would like to predict the fourth.
> Year 1 .37
> Year 2 .45
> Year 3 .46
> Do I average the change difference between Year1-Year2 and Year2-Year3???
> And then add the avg change onto the Year 3 value???
> Thanks in advance
> Jianying Zhang