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A test (typically of distribution, independence, or goodness of fit) or a family of distributions related to such a test.

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When to switch off the continuity correction in chisq.test function?

From this Research paper Table1 Association of RAD51-AS1 expression with clinicopathological features of EOC patients I see that p-value is calculated based on Chi-...
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Compare proportion of patient outcomes of the same group over time- McNemar's or Chi Square?

I want compare proportions for the same practices over two time points, while timepoint 1 is the control and timepoint 2 is an intervention. Let's say I have a design in which doctors are clustered ...
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Model Selection: Goodness-of-Fit Statistic when Noise is Unknown (vs Reduced Chi-Squared)

I have data D_k and different models M_i, and I would like to calculate a goodness-of-fit statistic for undertaking model comparison between the different M_i's, in the case of unknown uncertainties ...
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37 views

Chi Square test for lot of categorical variables

I have 36 categorical variables, 11 binary and other with more than 2 levels. I wanted to check if they are independent or not, so I want to do Chi-square test of independence. Problem is I believe ...
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Can feature selection found on a glm model be used for other models, based on the same dataset?

I want to train three different models for a supervised binary classification task. The models I am using are Boosted Logistic Regression, Neural Networks and Generalized Linear Models (GLM). After ...
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How to calculate chi-square when Observe value occurs in zero figure? [closed]

please solve my chi- square problem under independent ?
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How to compare multiple collocations based on their Chi2 score? How to find synonyms using collocation analysis

my question is regarding collocation analysis (i'm using R). I have following data gathered from Polish corpus: ...
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17 views

how to get p-values for each group in chisquare test of independence?

I got this following table using xtabs. ...
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Chisquare for homogenity on subsets of samples for more detailed statements?

I have two samples of six treatment groups. The outcome is an amount of positives. The treatments in both samples are the same, the measured outcome is different but dichotomous in both samples. I ...
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2answers
28 views

Most appropriate test to assess difference between categorical variables? Chi2 or Stuart-Maxwell?

I am trying to determine the most appropriate test for parts of my dataset. I have been using a $\chi^2$ test, but I am now realising it might not be the most appropriate. I am using Stata. I have a ...
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21 views

Fisher's exact / Chi-squared tests with repeated/dependent observations

I have a dataset (structure explained below) for which I want to perform some tests on 2x2-tables. The data is generated from a (randomized) experiment, and structured as follows: I have n subjects, ...
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Test for Uniform Distribution

The data I have has 24 data points for each observation. Each data point can take value of either zero or one. I want to test whether the 24 values come from a (discrete) uniform distribution. What ...
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1answer
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How to interpret chi2 p-value?

I performed a haplotype analysis for two SNPs in case/control study by web-based SHEsisPlus platform. For one the haplotype, the result was Chi2=54.898, p=1.27e-13. How to interpret this p-value?
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1answer
36 views

How to compare $t$-tests to $\chi^2$-tests for feature selection

I am trying to learn feature importance for an ML model. To do this I am running a univariate statistical test between each independent feature and the dependent variable I am trying to predict. The ...
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Is 'Significance test for Lasso' justified?

Lockhart et al described a "Significance test for the lasso", the motivating example for which is forward variable selection in a linear regression. In their Figures 1 and 2 they show Q-Q plots of a ...
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1answer
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Use of Chi Square for only semi-independent sample?

I ran a study for my Master's thesis that counted the number of people who attended different courses that were advertised in different ways, and how many passed/failed each. I used a Chi Square ...
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1answer
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What hypothesis test should I use to compare the overall performance of two different athletes in a 100m race?

I am sourcing data from IAAF's website to test my hypothesis - Athlete A is a better athlete than Athlete B (comparing their times in the Olympics). Since I would be sourcing the data from IAAF's ...
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0answers
10 views

feature selection of categorical variables using chi sqaure

i need to understand how to interpret these results for feature selction using chi square test . i have 43 categorical variables and target categorical variable and i want to select the top 12 ...
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1answer
29 views

Need help interpreting a chi-square Q-Q plot for multivariate normality

I would like to know if my interpretation is correct with respect to the Q-Q plot I made (see the first image below). The second image is a plot of a chi-square distribution. At the first half, it ...
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1answer
24 views

Statistical difference between multiple groups using percentage data

I have 3 groups of data. Group 1 contains 11 values, group 2 contains 7 and group 3 contains 11 values. The values are in the form of 'percentage change over time'. I would like to test to see if the ...
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37 views

How to statistically describe the right answer of a multiple choice question?

Participants need to identify the right strategy of several storyboards through a multtiple choice questions (7 possible answers). I collected 130 answers and now I want to show the significance that ...
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8 views

Compare occurrence of events

I have two groups of samples (A = 25 samples and B = 40 samples). In both of these groups can happen a series of events (or a series of groups of events classified as n-grams) that can happen ...
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1answer
27 views

Appropriate to do T-Tests on ordinal or binary data?

I have a data set of two groups of people, both are n=30 so n=60 total. I have administered a scale with 11 items which ...
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Correct statistical tests for significance of sequences

So I am trying to develop the correct statistical test in R to determine the following: I have 1000000 sequences each of five base pair length. Eg: Location: ATTTG ATGCG ...
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1answer
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Are there two types of Chi-square criterion?

I have seen two $\chi^2$ test across the internet. [Common wiki Chi-suqare test] To check whether a prediction is a good fit or not (a classical null test): Compute $\sum_{i=1}^{N} (x_i - \textbf{...
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31 views

Derive the distribution of the ANOVA F-statistic under the alternative hypothesis

Say we have $k$ samples of data, where sample $i$ is of size $n_i$ and we write it as $x_{i1}, ... , x_{in_i}$. Let the total sample size be $N$. The ANOVA model is $X_{ij} \sim N(\mu_i, \sigma^2)$ ...
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Analyzing monthly sex ratio

I have a data something like this. The numbers are the count of identified male and female of fish Decapterus russelli (Indian scad). I wanted to know if there's a difference in the sex ratio per ...
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8 views

Multiple Chi-square tests with MANY variables

I have two groups: group 0 and group 1 I have tested >1000 genes, of which are designated altered (=1) or not altered (=0) in each group. I would like to know whether the frequency of altered genes (...
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20 views

Can Chi-Sq Test be used to explore the independence of categorical variables on response variable?

I am investigating the independence of some categorical variables (apps, campaigns...) on the response variable (click through rate). I have some doubts on using Chi-Sq Test here: Chi-Sq Test can be ...
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1answer
54 views

Deriving $\chi^2$ density from the standard normal $Z$ density

For the sake of learning, I am trying to derive a $\chi^2$ density from the standard normal $Z$ density. The $\chi^2_k$ is a distribution of the sum of squares of $k$ standard normal variables, where ...
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3answers
63 views

Demonstrating that some exam questions are easier than others

Suppose there is an exam with 10 questions. Each question is worth 1 mark, and can be answered either correctly or incorrectly, thereby being either awarded the mark or not. 100 people take this ...
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Quantifying similarity of two objects in a population on certain characteristics

I have a set of objects (these are businesses) and for these businesses I have data on a number of characteristics. To keep this simple, we will consider these to be number of staff number of ...
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17 views

Detecting “biases” in model predictions with discrete and continuous features

I have a model that predicts a binary value based on a set of features for a data point. I want to be able to detect whether the predictions indicate any "biases" that aren't present in the data. For ...
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1answer
38 views

Type of statistical test for categorical variables?

What test am I supposed to use in this case: Categorical outcome [correct, partially incorrect, incorrect] Categorical predictors: Condition [2, 5 and 10 presentations of an image]. Time in which ...
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3answers
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How is the statistic $\frac{(Obs-Exp)}{\sqrt{Exp}}$ distributed as standard normal?

When testing deviations from an expected categorical distribution, the statistic $\Sigma\frac{(Obs-Exp)^2}{Exp}$ is commonly used and said that this statistic is distributed as $\chi^2$. From the ...
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further question on “simulate.p.value option in chisq.test in R ”

Thank you very much, Glen_b, for your reply to my question in the link, (simulate.p.value option in chisq.test in R). However, still I am confused in one point, you said that "however the fact that ...
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Appropriate statistical tests to see effect of an intervention on binned or categorical data

I am looking at the effect of an educational intervention on a classroom by examining the change in the students letter grades. Dummy Example: Test Cohort (100 students) Letter grade for each ...
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Distribution of quadratic form of multivariate normal with linear term

Suppose that $A$ is a symmetric non-random matrix and $X\sim N(\mu,\Sigma)$ and $b \in R^n$ is a non-random vector. Then what is the distribution of $$X^tAX+b^tX \quad ?$$ The distribution without ...
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Is this distribution Chi-Squared? [duplicate]

Let's assume $Y=\sum_{i=1}^{N}\alpha_iX_i^2$. where $X_i$ has Gaussian distribution with mean $0$ and variance $1$, i.e., $\mathcal{N}(0,1)$ and $\alpha_i$s are constants. When $\alpha_i$s are all $...
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1answer
24 views

Using chi-squared or binomial for triangle test of discrimination

Regarding beer taste testing. The wonderful people at Brulosophy do many experiments with beer, changing brew and fermentation methods and then using triangle tests to see whether there's a difference....
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simulate.p.value option in chisq.test in R [duplicate]

I have the low expected values problem in my data set and cannot solve with regular methods (e.g. combining levels, etc). I cannot use Fisher's test either because of the fixed marginals assumption of ...
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26 views

Testing the difference between two distributions

I have the following experimental setup: Protein A is capable of cutting protein B in small fragments. The small fragments are identified and the nature of the last amino acid in each fragment is ...
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17 views

Testing 3 Kruskal Wallis on 3 datasets that each has 3 treatments

I am not that experienced, but, I read a lot and seems am stuck to know if what i am doing is right or not. I have 3 datasets that each were initiated based on session duration. The 1st dataset has ...
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22 views

How to calculate mean and variance of non central chi distribution of the problem?

If $Y = \sqrt{\sum_{i=1}^N X_i^2} $, where $X_i \sim \mathcal{N}(\mu,\sigma^2)$, i.e. all $X_i$ are i.i.d gaussian random variables of same mean and variance, then what is the resultant PDF of $Y$? ...
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1answer
88 views

Relationship between the gamma distribution and Non-central chi squared distribution?

If $Y = \sum_{i=1}^N X_i^2 $, where $X_i \sim \mathcal{N}(\mu,\sigma^2)$, i.e. all $X_i$ are i.i.d gaussian random variables of same mean and variance, then what is the resultant PDF of $Y$? How the ...
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1answer
65 views

Chi Square versus Poisson distribution

In a study which analyses the effect of Lithium on suicide rates, the results were the following: Placebo group: 3 suicides in 83 patients Lithium group: 0 suicides in 84 patients My first approach ...
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Choosing bins for chi-square testing distributional fits for distribution similar to normal/heavy-tailed

Chi-squared test can be used to check the hypothesis, that given sample is from the given theoretical distribution. If the distribution is continuous then we should properly choose bins. Question 1 : ...
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1answer
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Chi-squared testing for say TWO samples from TWO distributions

Chi-squared test can be used to check the hypothesis, that given sample is from the given theoretical distribution. Assume as I have two samples (x1, ... xn) , (y1, ... ym) , and two theoretical ...
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Violation of Independence Sample

In almost all statistical testing, one assumption is that the sample is independent. But, the reality is that most time series data violate this assumption given that multiple events are generated ...