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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32 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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0answers
11 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} ~ ...
0
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1answer
28 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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0answers
19 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 ...
2
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0answers
23 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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0answers
53 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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0answers
48 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 ...
1
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1answer
61 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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0answers
30 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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0answers
51 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 ...
2
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0answers
40 views

multiple hypothesis correction for meta-analysis with missing p-values

I would like to combine multiple p-values (e.g., using Fisher or Stouffer), where some hypotheses may have missing p-values across studies. e.g., ...
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0answers
31 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: ...
2
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0answers
29 views

Alternatives to Fisher's method?

I'm using the Mann-Whitney U test to compare scores from a foreground (n ranging between 5-500) to a large background (up to 2000). Since my foreground is quite small I've been taking smaller random ...
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0answers
50 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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0answers
113 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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0answers
46 views

How do I calculate Fisher's LSD Familywise Error Rate?

I'm trying to compute Fisher's LSD Familywise Error Rate for an ANOVA using 6 treatments and an alpha level of .05. Since there are 6 treatments, there are a total of 15 pairwise comparisons, so I ...
4
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0answers
47 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 ...
1
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0answers
37 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 ...
0
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0answers
32 views

Type-II error and permutation tests

I am doing a permutation to know if two datasets are significantly different. These datasets, both, have a median of 1 (in fast, 60% of observations in one datasets and 80% of the other dataset are ...
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0answers
94 views

Integrating p-values (or z-scores) with missing values

I would like to apply a Stouffer (or Fisher) integration on a list of p-values or z-scores. However, some of them contain missing values. E.g. (R snippet): ...
4
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1answer
207 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 ...
0
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1answer
1k 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 ...
1
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1answer
1k 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: ...
1
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1answer
124 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 ...
0
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0answers
39 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 ...
3
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0answers
112 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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0answers
178 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 ...
4
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2answers
261 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 ...
2
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1answer
156 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 ...
2
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1answer
2k views

Fisher's method for combing p-values - what about the lower tail?

I have a bunch of independent p-values and now I want to combine them using the Fisher's method. Each of the individual p-values is coming from a one-sided test. I am just a little bit confused about ...
2
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0answers
277 views

Fisher's method when p-value = 0

I have a bunch of independent p-values and now I want to combine them using the Fisher's method. However, in R, when the p-value is zero, the log(p-value) becomes ...
1
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1answer
100 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 ...
2
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0answers
195 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 ...
5
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2answers
399 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 ...
4
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0answers
89 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 ...
3
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1answer
158 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 ...
5
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2answers
478 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) ) ...
2
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0answers
325 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 ...
0
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1answer
184 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. ...
2
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1answer
264 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 ...
7
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2answers
2k views

Fisher discrimination power of a variable and Discriminant analysis. Algebra of LDA

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 ...
0
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0answers
69 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 ...
4
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1answer
747 views

Fisher overall p-value vs. pairwise comparisons

I am doing comparisons on response rates across three sites. Following are the cell counts ...
7
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1answer
110 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 ...
1
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1answer
584 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 ...
0
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2answers
329 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 ...
6
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2answers
749 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 ...
1
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2answers
2k 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 ...
2
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0answers
1k 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 ...
5
votes
1answer
627 views

Understanding Fisher's combined test

I am using Fisher's combined test to fuse several different independent tests. I have a problem understanding the results in some cases. Example: Let's say I run two different tests, both with the ...