Non-parametric Tests Flashcards
Wilcoxon-test
when Wilcoxon Signed Rank Test is used?
Is used or single sample-equivalent to the ones used or the t.test
Wilcoxon-test
What is the Two-sample Wilcoxon-test useul for?
for hypothesis testing on population means from two samples.
General
when are the non parametricts test used?
when the form of the sampled population is unknown
not normally distributed
General
how does non parametric test work?
they transform our data into a normal distributed sample, so we can run tests upon.
Wilcoxon-test
how is the test statistic for Wilcoxon-test are equated?
The table below demonstrates how to perform the transformation and compute the test statistic. In short, (1) we compute the difference of each sample value from the hypothesized parameter, (2) rank the values from smallest to largest, ignoring the signs, and (3) then, we include the signs back in and compute the sum of the positive ranks (T+) and sum of the negative ranks (T-). The test statistic is smallest of the two.
Wilcoxon-test
what does the V shows in R?
In R, the V value corresponding to the Wilconox-test corresponds to the positive ranks sume.
Wilcoxon-test
What is Paired Wilcoxon-test useful for?
for hypothesis testing on population means from two paired samples, two data set orreponding to the same subjects changing over time (corresponding to the parametric test of paired t-test)
General
How do the parametric and non-parametric test differ?
The p-values can be dierent, being the p value of the non-parametric test a a stricter criteria for decision-making.
Kruskal-Wallis Test
when is Kruskal-Wallis Test used?
It is the non-parametric test equivalent to a one-way ANOVA test
Friedman’s test
when is Friedman’s test used?
It is the non-parametric test equivalent to a two-way ANOVA test
Testing for Normality
when is Shapiro-Wilk test used?
this test is used to corroboratere whether our data is normally distributed or not.
