The fisher tag has no wiki summary.
2
votes
1answer
42 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
votes
1answer
58 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 ...
3
votes
1answer
49 views
High level interpretation of Cramer-Rao bound and Fisher information matrix
I am reviewing a manuscript and am struggling to understand why some statistical techniques were chosen, i.e. what information they can give. The paper looks at the effect of predicting a variable ...
1
vote
0answers
54 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
vote
1answer
36 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
votes
0answers
27 views
Chi-square vs Fisher's exact test with infection data
I have data from an infection that I did and I'm trying to figure out if the differences I have observed are significant or not. I have infections with 4 different bacterial strains, with 10 mice ...
1
vote
0answers
42 views
Fisher information for Poisson Model
Assuming the data structure given below,
$$
\left[\begin{array}{l|l}
y & x \\ \hline \hline
y_{1} & x_{1} \\
y_{2} & x_{2} \\
\vdots & \vdots \\
y_{n} & x_{n} \\
...
0
votes
0answers
68 views
Fisher's exact test 2 x 4 contingency table possible to test one-sided?
Is it possible to test a one-tailed hypothesis with Fisher's Exact for more than a 2x2 contingency table? I am asking because the online calculators I found for this case only give a 2-sided value, ...
1
vote
1answer
56 views
Can I partition a frequency table and use Fisher's exact test instead of Chi Square test?
I am working with very small cell counts, and am wondering if Fisher's exact test can be used in place of Chi Square test when partitioning IxJ tables. I am interested if the same process for ...
2
votes
0answers
44 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 ...
0
votes
0answers
25 views
Different kind of scaling matrices
I was reading through a publication and it suggested there are different kinds of scaling matrices. They suggest the use of the fisher information matrix and I never heard it referred to as a scaling ...
2
votes
2answers
64 views
Should I use Fisher's exact test for this?
I'm relatively new to statistics and I'm a little confused about which test I should be using for this problem.
Let’s say I am collecting data about responses to a book under two different conditions ...
0
votes
0answers
68 views
2
votes
2answers
148 views
Interpreting p-values
I am a little confused about what p-values mean under Fisher's signficance testing & Neyman-Pearsons hypothesis testing.
Fisher uses p-values as a continuous measure of evidence against a null ...
4
votes
0answers
54 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
votes
1answer
86 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 ...
4
votes
2answers
125 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) ) ...
0
votes
0answers
45 views
Theoretical question about Hotelling and LDA
I have been studying Hotelling $T^2$ stat as the univariate t test on a linear combination on the original multiple variables.
The procedure follows like this:
Reduce dimensionality by creating a ...
2
votes
0answers
113 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
votes
1answer
44 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
votes
1answer
93 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 ...
2
votes
1answer
123 views
Fisher discrimination power of a variable and 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 ...
0
votes
0answers
43 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 ...
5
votes
1answer
221 views
What is the Fisher Information for the truncated poisson distribution?
The zero-truncated poisson distribution has probability mass function:
$P(X=k) = \frac{e^{-\lambda}\lambda^k}{(1-e^{-\lambda})k!}$, $k=1,2,...$
And the expectation of the truncated Poisson ...
0
votes
0answers
53 views
Which test to compare two datasets?
I have used a stimulus (stimulus1) in a perception test, to see if the participants perceive it as A or B in a forced choice task. (the stimulus is composed of several features f1,f2...)
Then I have ...
4
votes
1answer
193 views
Fisher overall p-value vs. pairwise comparisons
I am doing comparisons on response rates across three sites. Following are the cell counts
...
0
votes
3answers
197 views
Direction of relationship in 2x2 contingency tables
I've been studying contingency table analysis and got to experiment a little bit with Fisher's exact test and Fisher's power test. Now I want to be able to determine the direction of the ...
4
votes
1answer
45 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
vote
0answers
37 views
Taking Expectations for Fisher Information/Jeffreys' Prior
I've been working through a few examples of the Jeffreys' prior; however, I'm a little confused by one section. I was hoping that somebody could provide some clarification.
If the Jeffreys' prior is ...
1
vote
1answer
124 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
votes
2answers
190 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 ...
0
votes
0answers
271 views
Two-sided p-value of Fisher's exact test
For a paper I use Fisher's Exact Test in R. As I already found out the p.value in R is calculated as the sum of all probabilities of the hypergeometric distribution with the given parameters lower or ...
6
votes
2answers
149 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 ...
0
votes
1answer
140 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 ...
4
votes
1answer
223 views
How to report results of Fisher's test for larger than 2 by 2 tables
This is probably a very easy question but what is an acceptable phrase for reporting a Fisher's test where the number of rows and the number of columns are both $>2$. An example in R:
...
1
vote
1answer
337 views
Fisher's exact test for results of Wilcoxon-Mann-Whitney
I have two groups of subjects (9 and 13 people). And data from two condition for this groups. In each condition for each subjects I have some measurements. But number of measurements are different for ...
2
votes
0answers
418 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 ...
0
votes
1answer
149 views
Need help understanding how to implement Fisher's exact test [closed]
I want to see there is a connection between illness and age.
My teacher said that after categorizing the data I use the $\chi^2$ test, but also said the $\chi^2$test is not valid and I should use ...
4
votes
1answer
172 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 ...
1
vote
2answers
151 views
Testing if short sequence of small values drawn from binomial distribution
An experiment was run 10 times in configuration a and there were A failures, 10 times in configuration b giving B failures, 10 times ... (in all 9 different configurations). I have a list of 9 ...
15
votes
4answers
598 views
How to rigorously define the likelihood?
The likelihood could be defined by several ways, for instance :
the function $L$ from $\Theta\times{\cal X}$ which maps $(\theta,x)$ to $L(\theta \mid x)$
the random function $L(\cdot \mid X)$
we ...
2
votes
1answer
187 views
Fisher Test in R
Suppose we have the following data set:
Men Women
Dieting 10 30
Non-dieting 5 60
If I run the Fisher exact test in ...
0
votes
0answers
45 views
F ratio and model comparison method to compute confidence bounds
I am working with Fisher Ratio. I compute this ration from a function that was already implemented in the software I am working on. But I would like to be sure that it does what I think it does. ...
3
votes
1answer
978 views
Spearman's rank correlation for a beginner: Sample size and Interpretation
I am a computer scientist performing research, which includes calculating the Spearman rank correlation of two lists, one ranked by a human, another by a computer program.
I have the following ...
4
votes
1answer
243 views
How to run K-means clustering on data points of varying dimensionality?
I'm trying to aggregate $T$ local image descriptors (i.e. histograms) into a vector, namely, the Fisher Vector as described in this paper by H. Jégou et al., Aggregating local image descriptors into ...
0
votes
1answer
774 views
How to calculate probabilities for a 4 by 2 table?
I have collected data about test subjects which are classified into 4 categories, and I want to calculate the probabilities (odds ratios?) of developing some condition for a test subject in one ...
1
vote
3answers
132 views
Which kind of statistical test should I try for a sample with bivariate data?
I'm trying to analyze data from a questionnaire, showing graphical results. I used dispersion charts for correlating bivariate data with continuous and discrete ranges, showing also a trend line on ...
2
votes
1answer
596 views
How to handle missing data when determining differences between groups using Chi-square or Fisher's exact test
I have 168 rows of patient data: 104 controls and 64 cases. I want to know if albumin status (low or high) is related to case/control status. I made a table using R:
...
2
votes
1answer
492 views
Effect size for Fisher's exact test?
Does anyone know a way to calculate the effect size of a Fisher's exact test? Does that even make sense?
Thanks
1
vote
1answer
253 views
Alternative argument in Fisher test in R
Can anyone please tell me what the alternative argument is in fisher.test in R? What do greater and less imply?
...
