```Date: Thu, 20 Mar 2003 08:37:47 -0500 Reply-To: Art@DrKendall.org Sender: "SPSSX(r) Discussion" From: "Arthur J. Kendall" Organization: Social Research Consultants Subject: Re: I need help!!! Comments: To: Lana Content-Type: text/plain; charset=us-ascii; format=flowed If you look at the formula for the two sample t-test, you'll see that that it has the two variances (SD squared), one for each group in the denominator. The one sample t-test against a constant is the two-sample t-test with the error term for the second group resolving to zero. a kludge: If you cannot get Exner's SD, use yours for the second mean but turn it into a SE using 600 df. You can use matrix input in ONEWAY with 2 groups to learn about this. With one numerator df, F = t**2. If you can get the SD from Exner, try this all 3 ways. 1) with Exner's SD. 2) with a zero for Exner's SD 3) with your sum of squares scaled as if you had 600 df. The two means remain the same in each of the 3 runs. Use one of the "post hocs" designed for unequal variances. Hope this helps. Art Art@DrKendall.org Social Research Consultants University Park, MD USA (301) 864-5570 Lana wrote: > I am working on my dissertation and am stuck on figuring out which > statistical test to use. I'll try to explain what I am doing, I hope > you can help me. > > I am hoping to compare a group of individual's test scores (N=43) (my > sample) to a given norm group (Exner's norms on the Rorschach) (my > control group). Exner has 600 subjects in his sample. I tried to do > a one sample t-test on this, comparing my numbers to a "known number" > (i.e., the mean that Exner got in his normative sample). However, my > supervisor told me that he did not believe that this was the right > statistical test since the groups should have different degrees of > freedom. Please help me select a statistical test. I would really > appreciate it. Thank you!!! Marlena > ```

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