Date: Sat, 9 May 2009 10:06:37 +0200 Marta García-Granero "SPSSX(r) Discussion" Marta García-Granero Re: hypothesis testing for difference between two means <6.2.1.2.2.20090508133512.045f80b0@hawaii.edu> text/html; charset=ISO-8859-1

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> Hi<br> <blockquote cite="mid:6.2.1.2.2.20090508133512.045f80b0@hawaii.edu" type="cite">At 10:32 AM 5/8/2009, jimjohn wrote: <br> <blockquote type="cite">does anyone here know how to compute hypothesis tests/confidence intervals <br> for the difference between two means in SPSS? For example, I am comparing <br> the volume growth of my certificates with balance less than \$1000 versus the <br> volume growth with balances greater than \$1000. I want to see if the <br> difference in the two means is statistically significant. Any ideas? I don't <br> think comparing means does it because it has something about grouping and <br> factors. thanks! <br> -- <br> </blockquote> </blockquote> IF I understand your question correctly, "balances" is not categorical, but quantitative too. the t test can be used, without having to dichotomize balances.<br> <br> See this example, using the General Survey data that comes with SPSS. Suppose we want to compare number of children between those who have less than 12 years of education vs those who have 12 or more years. Instead of defining two groups, just use the cut-off:<br> <br> GET FILE='U.S. General Social Survey.sav'.<br> <br> T-TEST<br> &nbsp; GROUPS = educ(12)<br> &nbsp; /VARIABLES = childs.<br> <br> Anyway, I also agree with ViAnn: you are throwing away a lot ofinformation. See "Altman DG, Royston P. (2006) <a href="http://bmj.bmjjournals.com/cgi/content/full/332/7549/1080"> The cost of dichotomising continuous variables.</a> <b>332</b>, 1080. "<br> <br> HTH,<br> Marta<br> <br> <br> <br> <pre class="moz-signature" cols="72">-- For miscellaneous SPSS related statistical stuff, visit: <a class="moz-txt-link-freetext" href="http://gjyp.nl/marta/">http://gjyp.nl/marta/</a></pre> </body> </html>

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