Linked Questions
77 questions linked to/from How to choose between t-test or non-parametric test e.g. Wilcoxon in small samples
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Performing a t-test with discrete (currency) data
I want to perform a 2 sample t-test assuming unequal variances, however my variable is currency. Currency is discrete, however when checking the assumptions of the t-test, I see that the data should ...
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Alternative to T-Test
I have a series of values and I need to test if the returns are > 0. The t-test assumes normality, so I was wondering if there are other alternatives. Note that the standard suggested sample size is >...
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Wilcoxon signed rank test for paired, dependent observations
I have paired data, but repeated observations, which make the data to be paired with dependent observations. I read Wilcoxon signed rank test assumes the observations are independent.
Which test can ...
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Paired T test vs Wilcoxon signed-rank
I am trying to determine whether a paired T test or Wilcoxon ranked sum test is more appropriate to test for significance of improvement in the following:
Patients were surveyed for pain scores ...
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Statistical tests for uneven groups
We performed an experiment (usability testing), which had two independent samples, one group with 5 participants and the other with 24. Based on the analysis of the distribution of the data (Shapiro-...
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Understanding Bartlett's test from SAS
I am trying interpret the results of Bartlett's test run in SAS. This is the output I get:
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How to apply Wilcoxon test to small sample with NAs?
I have the following data which show some values before and after a drug. I want to test whether the drug increased the mean. I think I should use Wilcoxon test, but I don't know what to do with ...
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Parametric vs nonparametric methods [duplicate]
Are non-parametric methods preferable to parametric methods since the former do not force the model to have a parametric structure?
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Do I have to standardize my data to calculate variance?
I have 2 groups/samples.
Correct me if I'm wrong, but before doing an independent-group t-test we have to verify the homogeneity of variance with Hartley's F-max test.
When doing this test, we have ...
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What are the three forms of the Park test for heteroskedasticity?
I understand the Park test for heteroskedasticity has three different forms. The best known one is in a log form: LN(Residual^2) = intercept + slope (LN(X)). The second one is in a linear form: ...
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Outlier detection and normality assumption
So I am following this applied statistics class, and we were taught 5/6 tests for outlier detection and normality test, then told to apply these to some datasets. I am quite confused on how to go for ...
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How to compare two variables with different distributions?
I want to compare 2 independent variables, but the problem is that the first variable is normally distributed, while the second variable is not. What is the appropriate test in this case? Can I use an ...
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Is an F-test for equality of variance appropriate for a very large dataset?
I have a dataset with about 500,000 subjects and I am trying to establish whether the variance is equal. I first performed an F-test but then I realised the data is slightly skewed with kurtosis. So ...
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How to check statistical significance
I am from Civil Engineering background. In an experimental work, I am comparing some property (consider strength) of two materials/ mixtures "A" and "X". I prepared three specimens for each "A" and "X"...
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Data normalisation (transforming the data to normality)
I've got a reasonably large set of data from survey I got people to complete. After running a factored Shapiro-Wilk test on the data, the results came out that 86 of the 90 variable sets are ...
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