GraphPad Software Newsletter


FEBRUARY 2009 IN THIS ISSUE: Don't torture your data into faulty conclusions New stats book Submitting to journals using EPS Make a before & after graph with error & mean plotted XY graph with time scale Kick-start your project using Prism's sample data CURRENT VERSIONS CHECK FOR UPDATES Check here QUICKCALCS Free online calculators for radioactivity calculations, detecting outliers, t tests, ANOVA post tests, and more. CONTACT US Support central Email technical support Email customer service How to order Register your software GraphPad Software 2236 Avenida de la Playa La Jolla, CA 92037 USA www.graphpad.com		Free update for Prism 5! Prism 5 users can update for free to Prism 5 Windows 5.02 or Mac 5.0b. Download it today. This update adds functionality, fixes bugs and makes Prism 5 work on Netbooks. Don't use Prism 5? Try our free Prism 5 demo for a month without uninstalling prior versions. Files made with the Prism 5 demo can be opened by Prism 4.
		Data analysis insights:
		Don't torture your data into faulty conclusions Torture may get you the answer you want, but you need to be careful about false confessions. GraphPad founder Harvey Motulsky has some thoughts about why it's a bad idea to torture your data to obtain small P values. For statistical analyses to be interpretable, it is essential that all analyses be planned, and that all planned analyses be conducted and reported. These simple and sensible rules are commonly violated by rerunning statistical tests at multiple time points, with multiple subgroups, with sequential analyses, and more. Read more about data torture. More articles by Dr. Motulsky: How a lurking variable can confuse data analysis The pros and cons of using Excel for statistical calculations Fitting the pEC50
		Recommended book:
		A comprehensive encyclopedia of statistics David J. Sheskin has written a lengthy (1736 pages) statistics textbook that serves as an encyclopedia of statistics. He explains every variation on every test, with detailed examples and tables. The book has plenty of equations for those who want to do calculations themselves, but the concepts are explained in clear English. This makes it quite understandable by scientists (as well as statisticians). While it tries to be comprehensive, it does not deal at all with nonlinear regression. More details.
		Make these graphs:
		Prism makes it easy to make most graphs. But sometimes it can be a bit tricky to do something special. Click on the graphs below to learn how they were made. If you found a clever way to make a graph with Prism, please send it to us so we can include it in a future newsletter.
		Prism tips:
		Submitting to journals – Why vector EPS is the best choice Sometimes it seems like the hardest part of publishing your results is working with your journal to submit your figures. With Prism 5, we've added vector EPS output. EPS (Encapsulated Postscript) creates images that are crisper and smaller than TIFF files. And journals love them. We'd like to hear about your experience submitting GraphPad Prism files to journals. Use the Comments section at the bottom of the article to tell us how we could improve Prism to make your life easier. Kick-start your projects with Prism 5 sample data When we added sample data to Prism 5, we made a small mistake. We named this feature Sample Data. It is much more! Choose any graph type from the Welcome to Prism screen and instead of starting with an empty data table, choose a sample data set. You'll get a Prism file that includes sample data and step-by-step instructions that will walk you through creating your graph and analysis. These are a great way to learn how to use Prism. Once you understand the basics described in the samples, working with your own data should be easy.

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