All Questions
Tagged with nonparametric statistical-significance
110
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Statistical Significance Testing for Nested Cross-Validation in ML Experiment
I am currently working on an ML experiment where I use a nested 5-cross validation procedure and obtain a NDCG@10 scores for each test user. I am comparing 6 different ML algorithms and have data for ...
- 101
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57
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Welch ANOVA for Comparisons of Elevation & altered Sediment Accretion of Sea Ecosystems: Large DEM with no normal distribution & heterogeneity
I am investigating the elevation characteristics and sediment accretion effects of two distinct ecosystems within the Wadden Sea, impacted by the bioinvasion of one species (ecosystem one) and ...
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39
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Non parametric tests for 2 way anova and linear model? [duplicate]
My dissertation is due very soon and I have only just realised a large mistake in my work. I misread the normality test I used, which actually showed non normal data- but I still have homogeneity of ...
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10
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How to compare peak location and tail length of two different distributions?
I have the distributions of the fraction of people in each income bracket in a town in 1990 and 2020. The total sample size is the same in both, and assume that the incomes have been adjusted to ...
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48
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Doubt on non-parametric ANCOVA with two groups and pre-post scores and pre scores (baseline) as covariate
I have used a non parametric ANCOVA to analyze scores of a questionnaire (BSCS) with factors: Type of intervention(A and B) and timepoint (pre- and post) as well as baseline (same distribution as pre-)...
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28
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What test should I perform given repeated measures of one subject in three time periods?
I have data that represents the measurements of the concentration of PM particles in the air at different times (every hour of every day from 2018 onwards), and I am supposed to test whether the rules ...
- 101
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61
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Statistical significance test on 2-sample percentages
In the context of my thesis, i have created a corpus in order to compare the use of "z" vs "s" in specific words like organisation, organised, recognise, authorise etc.
I have ...
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1
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183
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What do these Wilcoxon values tell me?
I did a pre and post-test with a small number of students ($n=12$).These values came after a science intervention that took $4$ weeks. I used a Wilcoxon test for 2 related samples as there was not a ...
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2
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351
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SIgnificant ANOVA but not significant post hoc ... what can I do?
I am analyzing some IHC data on the density of cells in two brain regions(factor 1) in two closely related species(factor 2). My data is composed of an n of 6 for each species and is not normally ...
2
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1
answer
80
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What non-parametric test for multivariate binary data should I use?
I have two different groups of participants ("g" and "b") answering the same set of questions. Group "g" answered questions in the same order. Group "b" ...
- 21
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56
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Non-Parametric Test for Regression Significance
I have created a plot of the regression slope of sea surface temperatures (x) and an atmospheric variable (y). Although, I need to test the statistical significance of these trends using a non-...
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2
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163
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Multiple regression on unpaired data (A~B+C)
I am not sure how to test one of my hypothesis from my data.
Basically, I have 3 behavioral measures A, B and C, and I want to test that A is a composite of B and C: A = B+C
However, for practical ...
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3
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1
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217
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What exactly does the “symmetric distribution” assumption of the Wilcoxon signed-rank test refer to? [duplicate]
I have two lists (or sets) of data that I would like to statistically compare. More precisely, I would like to check if the difference between data list one and data list two is statistically ...
- 307
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24
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Is there a statistical test for five groups with averages ONLY?
The data I collected was measuring plant shoot masses and these were extremely small, so I could only find the total mass of the shoots from 30 plants. Hence, I only have the mean and none of the ...
user387381
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174
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1
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485
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which non parametric test is best for ordinal data?
I want to to do the test where i have to check if first column which is income, and 1 shows < 500, 2 = 1000, 3 = 2000 income values from the data, and which the other column which is a dependent ...
- 31
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1
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513
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Wilcoxon signed-rank test with an additional covariate
Problem formulation
I have 5 strains on which I administered treatment and repeated the experiment two times independently. So my data looks something like this:
...
- 165
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31
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What type of test should be used in this case?
I have a pandas data frame with a target variable, which is binary (classes progressive / non-progressive), that I want to ...
- 699
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69
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When is the central limit theorem not applied?
I am trying to compare two matched samples. In total I have a sample of 34 people. Each patient receives two treatments, a C1 treatment and a C2 treatment. So each patient will be compared to himself ...
- 919
1
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1
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60
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Repeated Measures, or just measuring the same thing, repeatedly?
I understand what "repeated measures" denotes - given a set of subjects, if each subject receives more than one treatment, we call this repeated measures, or "within subjects." But ...
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1
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1
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172
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Interpretation of interaction coefficients and p-values with categorical predictors
Let's say that we have gene expression measurements from bacteria after heatshock. The expression changes are collected as log2 changes, and are approximately normal and centered around 0. Ribosomal ...
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134
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Alternative for Wilcoxon Test?
I'm ending my Master's Thesis, and I'm trying to figure out which test to use to calculate the significance of my data.
Basically, we measured the Free Kick biomechanical parameters of several ...
3
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1
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150
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Which non parametric test can be used for multiple repeated measures at the same site?
I have repeated monthly measurements of some variable at several different sites, so that I have 21 data points (21 months) for each site. Now, I want to see if there are significant seasonal ...
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What statistical analysis should I use [duplicate]
I have been measuring flux of CO2 in (mmol m-2 d-1) from two different rivers and I now want to do a statistical analysis using IBM SPSS but Im not sure where to start. One lake is showing negative ...
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229
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Which statistical test for comparing ratios of independent samples
I have two conditions: A and B. Under each condition two parameters were measured in triplicates: x and y. Both are independent from each other (meaning the first x value does not experimentally ...
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How to find out how much statistical difference is there between the two groups in mann whiney U test?
So, i applied mann whitney U test to find out the difference in salary between two groups( eg- gender - male and female). There is indeed a statistical difference between the groups.
Result of Mann ...
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39
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Appropriate test for two not-normally-distributed data samples
I have some data comparing training participants who experienced the same training course either face-to-face or virtually (via Zoom). I have two survey items I am comparing. Sample A is for virtual ...
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62
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Non-parametric or parametric t-test: which one to trust?
I have two simple bimodal distributions that I'm sampling from, and I know that they are actually exactly the same. In my setting, I collect one sample from each and compare them, i.e., I'm doing a ...
- 152
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1
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377
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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 ...
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6
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3
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351
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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 ...
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Testing tuples of response variables
I'm struggling with comparing samples with multiple response variables, where such variables have a strict precedence or importance order. For the sake of this exercise, let's assume that each sample ...
- 121
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478
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When is a hypothesis test appropriate? [closed]
For example, when would a hypothesis test bed used?
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107
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Calculate fraction of multiple tests for which the null hypothesis was rejected
Consider a test (e.g., a permutation test) that tests, at the individual level, if a binary event occured or not.
A paper that I was recently reading, for example, tested whether or not a pair of two ...
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240
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Whitney Mann U test vs Kolmogorov Smirnov for a highly skewed continuous variable
I would like to compare task time to completion distributions (measured in minutes) across two groups. The distributions are highly skewed (the means are 300 to 400 times larger than the medians) and ...
- 143
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37
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Can I use parametric and non-parametric tests for different groups in my data?
I have different transcript expression data (continuous variable) and genotype data (categorical variable with 3 levels).
Most of the transcript data is normally distributed so I would like to use a ...
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28
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Non parametric test to compare variances [duplicate]
I have two samples of same size but at least at one of them is not normal distributed (tested by Shapiro-Wilk-test). How can a compare the variances of theses samples? Especially, I want to know the p-...
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106
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Bounds for hypothesis testing with non-normal distributions
After doing randomized experiment with two variants (AB tests), I want to do hypothesis testing without the normal distribution assumption to compare their means. Since the samples sizes are different,...
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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
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1
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10k
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Differences between Mann-Whitney U and chi-square tests for if two-samples come from same distribution
In a textbook, it introduces the chi-square goodness of fit test to test independence between two variables (organized in a contingency table), which can also be used to test if m samples are likely ...
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2
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121
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What is the alternative for one sample z test?
I have a sample of 350 and I have to compare the anxiety score among different variables. I wanted to apply the z test to compare the means but my data is not normally distributed. Is there an ...
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3
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131
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Parametric hypothesis testing for non-normal data
Are there any methods to make parametric hypothesis testing assuming that data is sampled from a known but non-normal continuous distribution?
I'm glad to see a solution to any particular ...
- 338
3
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1
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83
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How to ascertain statistical significance for nonparametric tests if the sample size is small
In literature about nonparametric rank tests in event studies, I often encounter a variety of test statistics and authors often attempt to convince their readers that their methods overcome certain ...
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71
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Help with the Mann–Whitney U test
I am new to statistics and really struggling here. I would appreciate any help that I could get. I am supposed to use a non-parametric test (Mann-Whitney U test was suggested) to check the difference ...
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3
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208
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Parameter estimation when the likelihood function does not exist
The observations $Z_1,Z_2\cdots$ are i.i.d. We have
$$Z_k = \sum_{i=1}^\infty \frac{X_{ki}}{2^k}.$$
where the $X_{ki}$'s are i.i.d. with a Bernouilli$(p)$ distribution. If $p=\frac{1}{2}$ then $Z_k$ ...
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147
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Kruskal Wallis test gives significance, multiple comparision table doesn't
I'm comparing physico-chemical properties of 8 different kefir samples like viscosity at different storage times. I have 4 viscosity measurements for each group. When I conduct Kruskal Wallis test; ...
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2
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1
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450
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Which statistical test works for paired and grouped data?
I have a small set of samples of plants where I've made some changes to some but not others and want to know if there was any significant effect on the number of leaves as a result of this change. My ...
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446
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Multiple comparisons between two groups (non-parametric)
Update Added more details about the Experimental setup.
My experiment comprised two groups, control (N=25) and experimental (N=26). Each participant belonged to one group. Their performance has been ...
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20
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Statistical Comparison of Algorithms by User Ratings
I have an experimental setting where I compare 3 algorithms on the same dataset(n_sources), through user subjective evaluation of the produced outcomes(each algorithm does a different kind of sound ...
- 165
2
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1
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384
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Which statistical test to use for multi-modal and mixed type data?
I researched for hours but cannot find the direction for the right statistical test to use. Here is the situation for Population A and B:
When plotting this frequency distribution, it looks like this:...
- 207
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553
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Significance test with non-normal, bounded data?
I am attempting to do a one-sample significance test to determine whether a set of data differs from a given value (0 in this case). The issues I have with these data:
Non-normally distributed data, ...
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