8k views

### 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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2k views

### 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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10k views

### 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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4k views

### 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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1 vote
7k views

### 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: ...
1 vote
5k views

### 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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1k views

### 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 ...
1k views

### 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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1k views

### 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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2k views

### 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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558 views

### 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 ...
291 views

### 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"...