This website is intended
to support Statistical
Methods in Psychology, 7th edition by David C.
Howell. (If you are using the 6th edition, simply change the URLs by changing "methods7" to "methods6" in the address bar.) It
is intended to provide data that you can use for examples
exercises, answers to exercises (some of them), and other
you may find useful. In addition, I have tried to
material on topics that I don't discuss in the text, and
about where to find useful information on the web.
Over the years I have assembled a large number of web pages that discuss material that is not covered in the text but go beyond what the text does cover. For example, a standard repeated measures analysis of variance assumes that each subject provides complete data, but there are alternative models of analysis that relax that restriction. Similarly, I discuss the chi-square test at length in the book, but I don't seriously address the question of what you do when your categorical variable is measured on an ordinal scale. I cannot include all of this material in the text because it would probably double its length. So I am making that material available via the web. Some of these supplements will be fairly short, and some of them are quite long. I plan to make them available as pdf documents because, especially for the long ones, it is easier to print them out rather than work through them on your computer screen.
These files contain the data from most of the examples and exercises in the book. The first line of each file contains the variable names. Instruct your software to treat that line as variable names. In SPSS this is done simply by clicking the appropriate button on the second dialog box. These are ASCII files, and can be imported quite easily into any statistical software.
I have provided fairly complete answers to odd numbered questions. Where questions ask you to think of an example of something, or verify that your results are the same as the results obtained by software, I generally do not provide answers because there is little to provide. Students often complain that I don't provide them to the even numbered questions as well, but many instructors do not want all of the answers available.
Much as I try, assisted by copy editors and proofreaders, errors always find a way of sneaking in. When I find those, or when they are pointed out to me, I add an entry on the errata sheet and try to give credit where it is due.
There is a surprising amount of material available over the internet, and much of it can make the teaching and learning of statistics easier. I have provided links to those websites that I think are particularly useful. However links go bad for reasons completely beyond my control (e.g., the author changes the server on which her pages are posted) and you may get error messages. The easiest thing to do is to try to recover the material by dropping off the last bit of each URL and seeing if that gets you anywhere.
A Java applet is a program that can be included in an HTML document and run over the web. There are many of them out there, and they are useful to illustrate important concepts, to serve as statistical calculators for statistical functions, and to simply run analyses. I have links to several of these on the applet page.
The glossary is a list of terms and their definitions. The main one that I point to is one that I wrote, but many other people have written them and I point to theirs as well.
I often am asked questions that stimulate me to go further into a topic and to write a page (sometimes a very long one) discussing that topic. For example, the intraclass correlation coefficient is an important statistic that I did not have space to discuss in the text. There is a link to a discussion that I wrote about that statistic.
Some time ago Esther Leerkes, now at the University of North Carolina at Greensboro, and I wrote a manual on using SPSS. (Actually Eshter did all the hard stuff, and I made suggestions as she went along.) SPSS is the most commonly available software for statistical analyses, and is easy to use. But we were asked if we could put together an introductory manual. That manual can be found at the above link. It refers to a slightly earlier version of SPSS, but that should make no difference to your use of it.
NOTE!! I have made important changes in this manual on the web site for the "Fundamentals" book. The link above will take you there. Do not be confused by the fact that the background has changed.
At some other time I wrote another manual (I no longer recall why) that is a bit more fun to read, but is not as long. This one is called the Shorter Manual for lack of imagination. You can load it at the link above.
I have written a review of basic arithmetic to accompany a more introductory book that I read. I am always surprised how often people forget some of the most basic material--myself included. You may well know everything in this review, but if you don't, or knew it but don't remember it now, the review should be helpful.
I can't resist adding what is perhaps the best advice I have. If there is something that you don't understand, just remember that "Google is your friend." He certainly is mine. If you don't understand what Fisher's Exact Test is, or you don't like my explanation, go to Google and type in Fisher's Exact Test. I just did that and had 260,000 hits. You can't tell me that there isn't going to be something useful in there.
Last revised 3/30/2009