This tag is very ambiguous. Use it when none of our more specific tags will work better: [fishersexact], [fisher-information], [ronald-fisher], or [fisher-transform].

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Encoding a set of vectors into 1 vector

I have a set $X$ that contains a set of vectors $V_i$ and I want to create a vector $u$ that represents each set. $V_i \in X$, $u$ is a representation of $V_i$. What are the possible ways of doing ...
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63 views

Contradiction between confidence intervals and Z-test

I've got the problem with Z-test and confidence intervals. Z-test rejects null hypothesis (proportions are equal), but confidence intervals are intersect. Let us consider 2 companies. The proportion ...
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2answers
156 views

Implement Fisher Scoring for linear regression

I know there is an analytic solution to the following problem (OLS). Since I try to learn and understand the principles and basics of MLE, I implemented the fisher scoring algorithm for a simple ...
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0answers
55 views

xtunitroot fisher interpretation

I would like to test if one of my variables is stationary (unemployment) with the xtunitroot fisher test. First, I do NOT include "trend" in the command and then I include "trend" - the results ...
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1answer
59 views

Fisher z-transformation and normality

I have 100 50x50 correlation matrices, which I have all Fisher z-transformed. I understood that this results in the all the entries of one matrix being approximately normally distributed. Questions ...
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1answer
22 views

Domain of Fisher z-transformation

We use the Fisher z-transformation for our correlation matrices, s.t. we arrive at approximately normally distributed data. As you might now, the Fisher z-transformation is equivalent to the function ...
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1answer
140 views

Boschloo or Barnard? Which Test for Cross Table Analysis?

Actually I am analyzing a 2x2 table from a small dataset of 30 patients. We are retrospectively trying to find some variables that give a hint about which treatment to choose. The variables (obs ...
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32 views

Which panel unit root tests should I use? Panel of 7 countries and 7 years

I have a balanced data of 7 years and looking into 7 countries. There are many panel unit root tests to be used. I am looking at using the Fisher-type and IPS tests but there are more than that and I ...
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56 views

Fisher LDA is a Bayes Classifier?

I've been going over many material in classification algorithms, and it seems that under the constraint that the covariance matrices are the same for a two-class problem then classifying a vector $x$ ...
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25 views

Non-negative Fisher LDA?

Is any one aware of any existing publication on non-negative solution for (Fisher's) linear discriminant analysis?. In particular: $$\text{maximize}_{w\geq0} ~ ...
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1answer
33 views

Using Fisher LDA in R

I have run a large study looking at traumatic brain injury in patients I have conducted CT scans on patients very soon after the injury as well as neurocognitive testing and then repeated this at 1 ...
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30 views

Re. Fisher LDA analysis in R

Please can I pick your collective brains I have run a large study looking at traumatic brain injury in patients I have conducted CT scans on patients very soon after the injury as well as ...
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0answers
35 views

Who first stated the relationship between ANOVA and linear regression?

ANOVA is usually thought as equivalent to linear regression, which is very interesting. Who first discovered this fact? Did Fisher know about this when he worked on ANOVA?
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61 views

Combinatorial Block Designs in Statistics

I am interested in description and references for how combinatorial designs (such as BIBD, Steiner triple systems etc.) are used in statistics (especially in designs of experiments and hypothesis ...
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233 views

Normalization before feature selection such as Fisher score (F-score)

The Fisher score (F-score) for feature selection is defined as in Combining SVMs with Various Feature Selection Strategies. However the paper doesn't mention any preprocessing to feature values such ...
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1answer
171 views

Linear discriminant analysis (Fisher) = Bayes?

I'd like to ask a question, I am reading book right now about mail filtering, both methods: naïve Bayes and Fisher are there very similar in implementation. I am also writing a paper on Bayesian spam ...
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45 views

Solution of Fisher LDA

I'm trying to understand the Fishers LDA. In the book I am using there is explained that one has to maximize expression $$\frac{\left( a^T\cdot \bar{x}_2-a^T\cdot \bar{x}_1 \right)^2}{a^T\cdot ...
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56 views

Average individual correlations or perform 1 set of correlations

First of all thanks for your time reading this post. I got some issue with correlation analysis that I am not able to solve at all as for more people I ask, different opinions I get (including ...
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43 views

Use Fisher's exact test to identify interactions?

Assuming that I have data with say 3 predictor variables and 1 response variable as such: ...
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72 views

I cannot use Fisher or Chisq test. What now?

I am trying to understand if there is a variance in the counts regarding two categorical variables. Gender Profession Salary F Teacher 12 M Teacher ...
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252 views

Fisher information matrix with negative eigenvalues, fix through singular value decomposition?

I have the following Fisher information matrix (just an example): ...
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64 views

Fisher test of periodicity

I have evenly sampled time series on which I applied Fourier transform. I am trying do determine if the signal contains statistically significant periodic components. I have succeeded with determining ...
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40 views

A/B testing on non-stationary populations

I am running A/B tests on a website. The daily engagement level of the users varies wildly, with a strong weekly seasonality. (Basically, users who are willing to use the software on Sundays are more ...
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1answer
289 views

What are methods I can use to calculate the two-sided Fisher exact test?

I am implementing code to compute the two-sided Fisher exact test of 2x2 contingency tables in C. I read that R's implementation is not the most efficient way to calculate the p-value for a two-sided ...
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1answer
2k views

Post-hoc Tests for Fisher's Exact Test

I am running a series of Fisher's test to analyse some 2x2 contingency tables with small values. I have found significance. Is there anything equivalent to Cramer's V or the Odds Ratio or some sort of ...
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1answer
2k views

Fisher's exact test in R - 2x4 table

I have a question on categorical data - I have a 2x4 matrix and I want to test the difference in the number of males or females in each group, and so I entered the data into R. So I input this: ...
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1answer
161 views

Sample variance Fisher consistency

I am reading conflicting references regarding the Fisher consistency of the sample variance. $$s^2 = \frac{\sum_i^n (x_i - \bar{x})^2}{n}$$ Could anyone explain me how to proof whether $s^2$ is ...
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40 views

Tests of independence for measurements of different magnitudes

Say there is a count table of observations Exon 1 Exon 2 Normal 1000 70 Disease 400 10 This gives a significant p-value if a ...
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116 views

Is Fisher overestimating the variance here?

[NB: the title of this post used to be "Please help me decipher Fisher on ANOVA". I've edited the question to make it more focused, and modified the title accordingly.] Since anything written by R. ...
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202 views

Test of Difference between 2 Sets of Pearson Correlations

Suppose I have two sets of Pearson correlation coefficients -- call them set A & set B, and they are of the same size. How do I systematically compare the correlations in A against B? E.g., I want ...
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2answers
281 views

Computing p-values

I am a computer engineer, living in a digital world. I have no probabilistic background besides a probability course in the University and tried to grasp the Fisher's idea and have got the following ...
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1answer
177 views

Distribution of p-values from multiple experiments

My experimental setup is the following: compute an optimal solution $S$ to problem $A$ on instance $I$, evaluate test statistic $f(S)$, compute $f(S_i)$ for $S_i$ $(0 \leq i \leq n)$ drawn from a ...
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1answer
106 views

how to calculate E[vech(x x')vech(x x')']?

Supposing a vector x follows normal distribution. I want to calculate the expectation of the "fourth moment" in a vector form, meaning $\text{E}[\text{vech}(x x')\text{vech}(x x')']$, given that we ...
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0answers
214 views

Apparent fallacy in Fisher-Irwin test

For a hypothesis $H_0\equiv p_1=p_2$ (for two Bernoulli distributions), we take a measurement and find that $X_1=i,X_2=j$, and we denote $k=i+j$ Now, to test $H_0$, the Fisher-Irwin test tells us to ...
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2answers
468 views

Interpreting p-values

I am a little confused about what p-values mean under Fisher's signficance testing & Neyman-Pearson's hypothesis testing. Fisher uses p-values as a continuous measure of evidence against a null ...
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92 views

Orthogonal intersection in a Riemannian manifold

Let $S$ be the set of all probability distributions on $\mathbb{R}$ and $S_n=\{p_\theta\}$ be an $n$ dimensional submanifold of parameterized family of probability distributions on $\mathbb{R}$ where ...
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1answer
178 views

Orthogonal intersection of linear family and exponential family

I asked the following question in MSE for which I couldn't get any answer yet. I thought this would be a better place for that question. In statistical maniolds ...
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2answers
856 views

Connection between Fisher metric and the relative entropy

Can someone prove the following connection between Fisher information metric and the relative entropy (or KL divergence) in a purely mathematical rigorous way? $$D( p(\cdot , a+da) \| p(.,a) ) ...
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0answers
359 views

Statistical significance of increase in correlation

I have a sample with some individuals, and also three variables measured for each individual, let's say $A$, $B$ and $C$. There is a mild correlation between $A$ and $B$ and a mild correlation ...
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1answer
227 views

How do you test for independence of k binomial variables?

I am analyzing some orthopedic data and our outcome is union vs. non-union of a fracture. One of our independent variables is whether or not the initial fracture was closed (skin intact) vs. open. ...
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1answer
286 views

Comparing two nominal-scale response distributions

I have data from an experiment that consist of nominal-scale responses that subjects made in two treatments (the treatments are between subjects, not repeated measures). I've provided my data in data ...
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2answers
3k views

Algebra of LDA. Fisher discrimination power of a variable and Linear Discriminant Analysis

Apparently, the Fisher analysis aims at simultaneously maximising the between-class separation, while minimising the within-class dispersion. A useful measure of the discrimination power of a ...
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71 views

Confidence intervals based on asymptotic normality

I wrote a report about confidence intervals based on asymptotic normality. However, my supervisor said that the definition in the second paragraph is wrong, but I ...
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1answer
845 views

Fisher overall p-value vs. pairwise comparisons

I am doing comparisons on response rates across three sites. Following are the cell counts ...
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1answer
129 views

Enrichment analysis by gene duplication level

Biological Background Over time, some plant species tend to duplicate their entire genomes, gaining an additional copy of each gene. Due to the instability of this setup, many of these genes are then ...
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1answer
651 views

How to compare two sequences of binary data?

I have two differing-length sequences of binary values. In each sequence, each value corresponds to an observation which is either right or wrong. I'm looking for a statistical test that addresses ...
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2answers
385 views

Fisher classification method for normally distributed classes

As a follow-up to my previous question, I want to use Fisher's classification method (I mean, projection method) to project the data given the fact that the two classes are normally distributed. How ...
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2answers
1k views

Fisher Distance for feature selection

I'm currently working for EEG signal classification from 3 electrodes. I want to have a simple feature selection algorithm that is independent with the classification process. From the feature ...
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2answers
3k views

Which one consider when dealing with dummy variables: Exact Sig. (2-sided) or Exact Sig. (1-sided)?

I'm running a cross tab of one categorical variable against a dummy variable. This dummy variable indicates the presence or absence of a company characteristic(if the company is industrial it should ...
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0answers
2k views

Gamma distribution and Cramér-Rao bound

There are two definitions of the GAMMA distribution: I did the ML estimation, generated the Fisher Information, compared it to the Variance and the Cramer Lower Bound was reached, so the estimator ...