Posted by
Maguin, Eugene on
Mar 19, 2014; 3:12pm
URL: http://spssx-discussion.165.s1.nabble.com/best-test-for-this-analyses-tp5724913p5724917.html
I know you've gotten a reply already but I don't completely understand the dataset. Two different tests, 33 people take each test in year 1. Do the same 33 people take each test in years 2 and 3? OR, like in a school, is it three groups of 33. Makes a big difference in the analysis. How much non-normality is there? What are the skew and kurtosis numbers?
Gene Maguin
-----Original Message-----
From: SPSSX(r) Discussion [mailto:
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Sent: Saturday, March 15, 2014 10:15 AM
To:
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Subject: best test for this analyses?
I would be greatful for advice on analysing this data in SPSS
A study was done of comparing test results (% correct responses) on two subjects biology and english. The tests are supposedly adjusted so as to be of equal difficulty (approx).
The study was done in 3 years of a school at the same time.
So we have 33 subjects in year 1 tested on biology and english (the same participants were tested twice, once in each subject - i.e. repeated
measures) from year 1, same for year 2, same for year 3 (total 99
participants)
SO the research question is whether there are differences on the basis of subject (i.e. do scores on biology differ significantly from those on
english) and whether performance improves over the years (i.e. is year 2 better than year 1, is year 3 better than year 2).
I was thinking ANOVA with multiple comparison tests. Problem is that normality tests show not normal distribution (KS And SW)
so then thinking kruskall wallis but the assumption of the variables having the same shaped distribution is not met (one has a positive skew the other negative).
I ran the kruskall wallis test anyway and it showed significant differences by year for one of the subjects (english)but not for the other (biology).
Even of I could use KW this still leaves the issue of how to do multiple comparison test with non parametric data, to find out which years differ from which. Reading suggests this is obscure process with non parametric data?
Then there is the other research question - hoe to test for significant differences on basis of subject?
Think I need to give this more thought bit any guidance much appreciated
Thanks
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