Wow, I'm glad to see TIPS back in action!
I wonder if anyone can help. I just found out I'm teaching a Human
Development class this semester and I have to develop the entire class but I
haven't taught HD before. I have no choice on the book, which is Human
Development, 9th Ed., by Craig.
I wanted to know if anyone had a syllabus that has worked for them that they
would be willing to share??? I have about 2 weeks to prepare.
Also, does anyone have any suggestions for interesting assignments or
exercises?
Haydee Gelpi
Broward Community College
Florida
-----Original Message-----
From: Russell T. Hurlburt [mailto:[EMAIL PROTECTED]]
Sent: Monday, August 06, 2001 3:35 AM
To: [EMAIL PROTECTED]
Subject: Re: computational formula - sum of squares
Judith--
Here 'tis.
sum (x-xbar)^2
= sum (x^2 - 2 x xbar + xbar^2)
= sum x^2 - sum 2 x xbar + sum xbar^2
now because 2 and xbar are constants
=sum x^2 - 2 xbar sum x+ sum xbar^2
now because sum x = n xbar
=sum x^2 - 2 xbar n xbar + sum xbar^2
=sum x^2 - 2 n xbar ^2+ sum xbar^2
now because sum of a constant = n times that constant
=sum x^2 - 2 n xbar^2 + n xbar^2
=sum x^2 -n xbar^2
now because xbar = sum x / n
=sum x^2 - n( sum x)^2 / n^2
=sum x^2 - ( sum x)^2 / n
--Russ
_________________________________________________________________
Russell T. Hurlburt, Ph.D. Email: [EMAIL PROTECTED]
Professor of Psychology Telephone: (702) 895-0194
University of Nevada, Las Vegas Fax: (702) 895-0195
4505 S. Maryland Parkway
Las Vegas, NV 89154-5030 USA
http://www.nevada.edu/~russ
Info about Comprehending Behavioral Statistics (2nd ed.)
is at http://psychology.wadsworth.com/authors/hurlburtr/cbs.html
_________________________________________________________________
Judith wrote:
SS = the sum of the squared scores minus the sum of the scores squared,
divided by the number of scores.
Does anyone know the mathematical proof for this formula's equivalence to
the definitional formula?
The definitional formula being:
SS = The sum of the squared deviations from the mean
