All Questions
Tagged with nonparametric statistical-significance
110
questions
32
votes
3
answers
5k
views
Why does the Kolmogorov-Smirnov test work?
In reading about the 2-sample KS test, I understand exactly what it is doing but I don't understand why it works.
In other words, I can follow all the steps to compute the empirical distribution ...
- 915
16
votes
1
answer
2k
views
When/where to use functional data analysis?
I am very new to functional data analysis (FDA). I am reading:
Ramsay, James O., and Silverman, Bernard W. (2006), Functional Data
Analysis, 2nd ed., Springer, New York.
However, I am still not ...
- 2,957
10
votes
2
answers
2k
views
Confused about the Mann-Whitney $U$ test. Does it test distribution equality (pdf) or just mean/median equality?
I am rather confused about the Mann Whitney test, many statements I read state it tests for distribution equality between two populations and some state it tests for means/median/central tendency only....
- 215
8
votes
1
answer
377
views
What is the parameter in Spearman's $\rho$
For Kendall's $\tau$ the parameter of interest is
$$E[\text{sign}(X_1-X_2)\text{sign}(Y_1-Y_2)]$$
where $(X_1,Y_1),(X_2,Y_2)$ are iid copies of $(X,Y)$.
The estimator is the famous Kendall's tau
But ...
- 183
8
votes
1
answer
5k
views
Differences between poisson.test and E-test when testing Poisson parameters
Suppose we have two independent Poisson-distributed variables $X_1$ and $X_2$. We want to test whether the Poisson parameters are equal, i.e. whether $\lambda_1=\lambda_2$.
Now we have 4 distinct ...
- 2,200
7
votes
3
answers
8k
views
How to test group differences on a five point variable?
I have a series of observations that fall into bins (or "scores"); that is, the data can be 0, 1, 2, 3 or 4. There are two groups of such data, control and treated. I know the number of individuals ...
John
6
votes
2
answers
942
views
Subsets not significantly different but superset is
I have various clinical data on participants in a study. I'm looking at a continuous variable ("A") and a (binary) categorical variable (group) ("O"). I used a Wilcoxon test in R (the data are not ...
- 1,261
6
votes
3
answers
351
views
T-tests provide info about the margin of mean difference?
I have 2 unpaired datasets where the difference of the sample means is quite substantial (with the naked eye). The t-test shows that the difference is significant (p-value=0.007) and I would like to ...
- 63
6
votes
2
answers
4k
views
How to interpret Mann-Whitney's statistical significance if median is equal?
Testing the difference between the observations of two groups by using Mann-Whitney Test has given the following output (from minitab):
...
6
votes
2
answers
5k
views
Which non-parametric test can I use to identify significant interactions of independent variables?
I have an experiment producing results (dependent variables) that don't pass tests of normality, thus I am testing hypotheses using non-parametric tests.
My DVs are continuous, while my factors (...
- 71
5
votes
1
answer
3k
views
What is the meaning of rank in the context of change-detection?
In a technique that uses CUSUM for change-point detection in this paper, the first step is given below:
Let $x_1, x_2,..., x_n$ be the $n$
samples in an event-series. The
samples are ranked in ...
- 4,542
5
votes
2
answers
553
views
What test is appropriate for comparing the difference in accuracy between recognition tools?
I have developed a tool that recognizes a set of six classes, and then tested and evaluated its ability to recognize these classes by using the F-score (aka F-measure). I then tested two other tools ...
4
votes
1
answer
3k
views
Should I use Chi Squared/Fisher's Exact Test or McNemar's Test?
Say I did a survey of 100 people asking if they eat vegetables daily. Out of my sample population, 60 say they do, 40 say they don't. Now, I also have the breakdown of males and females. Say in the 60 ...
- 1,505
4
votes
1
answer
81
views
Studying the distribution of the p-value?
I have two data vectors $X=(X_1, X_2, \dots, X_n)$ and $Y=(Y_1, Y_2, \dots, Y_m)$ where $X_i \overset{iid}{\sim} P$ and $Y_i \overset{iid}{\sim} Q$, and I am performing a two-sample test (i.e KS test ...
- 651
4
votes
0
answers
213
views
Nonparametric test for largely skewed count data
My research design looks as follows: an experimental game with 4 participants (human subjects), repeated for 20 rounds. During each round, participants are allowed to form bilateral coalitions which ...
- 53