Re: Student's t vs. z tests
Eric -- Good comment! Also, it is helpful to keep in mind that: t^2 (df2) = F(1,df2) -- Joe Joe Ward 167 East Arrowhead Dr. San Antonio, TX 78228-2402 Home phone: 210-433-6575 Home fax: 210-433-2828 Email: [EMAIL PROTECTED] http://www.ijoa.org/joeward/wardindex.html Health Careers High School 4646 Hamilton Wolfe San Antonio, TX 78229 Phone: 210-617-5400 Fax: 210-617-5423 - Original Message - From: "Eric Bohlman" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, April 16, 2001 3:43 PM Subject: Re: Student's t vs. z tests > Mark W. Humphries <[EMAIL PROTECTED]> wrote: > > Hi, > > > I am attempting to self-study basic multivariate statistics using Kachigan's > > "Statistical Analysis" (which I find excellent btw). > > > Perhaps someone would be kind enough to clarify a point for me: > > > If I understand correctly the t test, since it takes into account degrees of > > freedom, is applicable whatever the sample size might be, and has no > > drawbacks that I could find compared to the z test. Have I misunderstood > > something? > > You're running into a historical artifact: in pre-computer days, using the > normal distribution rather than the t distribution reduced the size of the > tables you had to work with. Nowadays, a computer can compute a t > probability just as easily as a z probability, so unless you're in the > rare situation Karl mentioned, there's no reason not to use a t test. > > > > = > Instructions for joining and leaving this list and remarks about > the problem of INAPPROPRIATE MESSAGES are available at > http://jse.stat.ncsu.edu/ > = = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: cite for using linear regression instead of logistic regression
David -- Logistic Regression is more appealing to some folks since it maps the Predicted values into the range 0-1. If you do a least-squares regression predicting a 0-1 dependent variable, the predicted values may not be mapped into 0-1 (e.g. some predicted values may be < 0 and some may be > 1. However, for "practical" decision-making such as "selection", "classification" the results will be the same. Since you brought up the question, I'm sure that the "logistic regression" folks can enlighten us on the "practical" advantages of "logistic regression". -- Joe Joe Ward167 East Arrowhead Dr.San Antonio, TX 78228-2402Home phone: 210-433-6575Home fax: 210-433-2828Email: [EMAIL PROTECTED]http://www.ijoa.org/joeward/wardindex.htmlHealth Careers High School4646 Hamilton WolfeSan Antonio, TX 78229Phone: 210-617-5400Fax: 210-617-5423 - Original Message - From: "David Duffy" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, March 18, 2001 8:41 PM Subject: Re: cite for using linear regression instead of logistic regression > Scheltema, Karen <[EMAIL PROTECTED]> wrote:> > > I've read several times on this listserve comments from people that when> > p(y) is not extreme, a logistic regression model can be estimated by a> > linear regression model.> > Some references cited by Harvey (1982): also BF&H> > Harvey WR (1982). Least squares analysis of discrete data. J Anim Sci> 54: 1067-1071.> > Cochran WG (1940). The analysis of variance when experimental errors follow> the Poisson or binomial laws. Ann Math Statis 11: 335.> > Cochran WG (1943). Analysis of variance for percentages based on> unequal numbers. JASA 38:287.> > Li JCR (1964). Introduction to statistical inference I. Ann Arbor: Edwards.> > -- > | David Duffy. ,-_|\> | email: [EMAIL PROTECTED] ph: INT+61+7+3362-0217 fax: -0101 / *> | Epidemiology Unit, The Queensland Institute of Medical Research \_,-._/> | 300 Herston Rd, Brisbane, Queensland 4029, Australia v > > > => Instructions for joining and leaving this list and remarks about> the problem of INAPPROPRIATE MESSAGES are available at> http://jse.stat.ncsu.edu/> =
Publisher Contacts
Greetings-- I occasionally receive inquiries about the contacts for various publishers. Here is the latest information about Bedford/St.Martin's, W.H.Freeman and Worth Publishers -- David Moore books. -- Joe P.S. -- I have no monetary involvement with these publishers. **** Joe Ward 167 East Arrowhead Dr. San Antonio, TX 78228-2402 Home phone: 210-433-6575 Home fax: 210-433-2828 Email: [EMAIL PROTECTED] http://www.ijoa.org/joeward/wardindex.html Health Careers High School 4646 Hamilton Wolfe San Antonio, TX 78229 Phone: 210-617-5400 Fax: 210-617-5423 HIGH SCHOOL TERRITORIES HS Assistant: Jessica Van Komen, (888) 254-1356, [EMAIL PROTECTED] 20A Jennifer Watterson 888-254-1365 [EMAIL PROTECTED] Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont Colorado, Iowa, Kansas, Missouri, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Wyoming 20B Melisa Doyle 888-254-1358 [EMAIL PROTECTED] DC, Delaware, Georgia, Maryland, North Carolina, South Carolina, Virginia, West Virginia, Florida 20C Cynthia Rorick 888-254-1360 [EMAIL PROTECTED] Alabama, Arkansas, Illinois, Indiana, Kentucky, Louisiana, Michigan, Mississippi, Ohio, Tennessee, Wisconsin, Minnesota 20D Melissa Segelke 888-254-1351 [EMAIL PROTECTED] Alaska, Arizona, California, Canada, Hawaii, Idaho, Nevada, Oregon, Utah, Washington 20E Cindi WeissGoldner (800) 470-4767 ext. 552 [EMAIL PROTECTED] New Jersey, New York, Pennsylvania = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
