Robert, We unfortunately do not have enough information to help you interpret the results, and this is not really an R question at all, but general statistical advice. You will probably have much better understanding and confidence in your results by consulting a local statistical consultant at your university.
The values shown for sample 1 and sample 2 lead me to believe that these are not drawn from a homogeneous population. Whoever ends up helping you is going to need to know how these measurements were obtained in much greater detail than you've given here. Best Regards, Erik Iverson -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Robert Hall Sent: Wednesday, September 16, 2009 1:55 PM To: r-help Subject: [R] T-test to check equality, unable to interpret the results. Hi, I have the precision values of a system on two different data sets. The snippets of these results are as shown: sample1: (total 194 samples) 0.6000000238 0.8000000119 0.6000000238 0.2000000030 0.6000000238 ... ... sample2: (total 188 samples) 0.80000001 0.20000000 0.80000001 0.00000000 0.80000001 0.40000001 ... ... I want to check if these results are statistically significant? Intuitively, the similarity in the two results mean the results are statistically significant. I am using the t-test t.test(sample1,sample2)to check for similarity amongst the two results. I get the following output: ----------------------------------------------- Welch Two Sample t-test data: s1p5 and s2p5 t = 0.9778, df = 374.904, p-value = 0.3288 alternative hypothesis: true difference in means is not equal to 0 95 percent confidence interval: -0.03170059 0.09441172 sample estimates: mean of x mean of y 0.5138298 0.4824742 ------------------------------------------------ I believe the t-test checks for difference amongst the two sets, and p-value < 0.05 means both thesets are statistically different. Here while checking for dissimilarity the p-value is 0.3288, does it mean that higher the p-value (while t.test checks for dis-similarity) means more similar the results are (which is the case above as the means of the results are very close!) Please help me interpret the results.. thanks in advance! -- Rob Hall Masters Student ANU [[alternative HTML version deleted]] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
