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

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Alternatives for chi-squared test for independence for tables more than 2 x 2

What are some alternatives to the chi-squared test for categorical variables with tables larger than 2 x 2 and cells with a count less than 5, if I don't want to merge classes?
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1answer
17 views

chi-squared to test if two variables have the same frequency distribution

I want to test if x and y have the same frequency distributions using chi-squared. In my code below, I've concluded that because ...
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1answer
25 views

Why need to combine the bins when do Chi-square test

From Chi-Square Goodness-of-Fit test, It says If some of the counts are less than five, you may need to combine some bins in the tails. So how to understand this?
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15 views

Independent and dependent variable [on hold]

For each statistical test, describe the criteria for both the Dependent and Independent variable: Student t-Test Chi-square test
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23 views

25% are significant, can't be right

A couple of classes (like in school) did a test and each pupil solved a couple of problems. Classes are grouped by a small range of the average over the pupils total. I calculate the expected value ...
3
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1answer
23 views

Possibility to run multiple chi-square tests on 2x5 table

I'm analyzing data in which I have a dependent variable with two possible outcomes (yes or no) and an independent variable with five emotion conditions, neutral, angry, sad, ashamed, and afraid. The ...
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1answer
25 views

Test of proportions or chi-squared? [duplicate]

These data are from an A/B test of free trials to conversion. Someone can sign up for a 30 day free trial of the product. If they like it they stay on and become paying customers. By default (A), ...
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21 views

Effect size for goodness of fit chi-square

I would like to assess the effect size of a goodness of fit chi-square test. I have a variable that can have 3 states and test against a custom expected value. I used a variation Cramér's V for a ...
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20 views

Which test do I need to apply for repeated measures?

My research question is as follows: How does on-ground presence of bird species A, B, and C change in relation to: 1. species A breeding chronology, and 2. time of day/month My data consists of ...
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21 views

What to do after a significant Exact test?

I have significant Fisher exact tests for a 2x3 and 6x3 contingency table. All I can get from it is that the observation regarding columns and rows are not random. But I don't know which combination ...
2
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1answer
36 views

How to represent goodness of fit for multiple least squares fits

I have many sequences (~50) of time series data that I have fit to a non-linear model using a least squares fit. If I had a single sequence of time series data, and I fit a model to it using a least ...
0
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1answer
57 views

Expected values vs. fitted values from log-linear model

Let's consider, for instance, a table like this one, with two independent categorical variables: x <- Titanic[,,2,1] I want to model this contingency table ...
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1answer
29 views

Observed / expected vs odds ratio

I am trying to understand the difference between the O/E ratio vs the odds ratio. I think the odds ratio can handle small samples better than the O/E ratio. I am wondering if anybody has more ...
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14 views

goodness of fit vs independence test in finite population case

I have a finite population frame. Around 80% of the frame members have e-mail addresses, and a survey was sent via e-mail to those people. Roughly 20% of those to whom e-mails were sent replied to the ...
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11 views

Using F-Statistic and Critical Value to infer Chi Square and P-value

I'm currently running the Granger Causality Test on MATLAB to determine whether the behavior of a set of swaps affects another set of swaps. However, my MATLAB code only appears to be producing ...
2
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1answer
76 views

chisq.test and wilcox.test don't concord with my graphs and observations?

I want to know if a factor variable have an incidence on another variable (dura). For example : ...
1
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1answer
25 views

How can I analyze / compare point-of-sales data between stores with different product offerings?

Let's say I have two stores, A and B, and let's say I have two products in the same department: product 1 and product 2. Let store B have product 2 which store A doesn't have, both stores have product ...
2
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1answer
33 views

Chi Squared Kernel and Faster implementation

There is a good implementation of Chi-Squared Kernel in http://www.vlfeat.org/matlab/vl_alldist2.html But this implementation is very slow when input data is huge. This implementation doesn't accept ...
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11 views

sadists package/ Sum of (non-central) chi-squares to a power

I try use "sadists" package in R to compute quantiles and probabilities on sum of non-central chi-squares distribution, but there are some issues in this package. I give an example: wts = ...
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21 views

What are the different ways to discretize continuous features?

I'm working on classification problem. I have a set of continuous & discrete features and I'm trying to list my features in their order of significance. Using chi-squared test as a filter & ...
3
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2answers
81 views

Difference of two squared normal dependent variables

I need to find the distribution of the random variable $Z$ $Z = \frac{(X - \mu_0)^2}{\sigma_0^2} - \frac{(X - \mu_1)^2}{\sigma_1^2}$, where $X \sim \mathcal{N}(\mu_0, \sigma_0)$. We can find the ...
0
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1answer
73 views

R: prop.test - Chi-squared approximation may be incorrect

I am trying to compare the proportions of two populations, using prop.test My data is straightforward - first population is 6/26 and second is 15/171. I am trying ...
0
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2answers
25 views

how best test for differences among two samples of abundance (count) data measured at the same sites

I want to test for differences in the abundance (counts) of two types of lizards. Both types were sampled at the same sites (n=284). The distribution of both types is overloaded with zeros and lizards ...
3
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1answer
39 views

How would combining levels in a contingency table (2x3 $\rightarrow$ 2x2) affect the power of a chi squared test?

A 2x2 table has a critical $\chi^2$ value of $3.84$, whilst a 2x3 table has a critical value of $5.99$ (for a significance level of $0.05$). Is it reasonable to think, that if you are able to turn ...
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62 views

Is there an alternate $\chi^2$ calculation useful for data spanning a large scale?

I have experimental small angle scattering data which provide information about the structure of a molecule. I can use a PDB file of a molecular structure (contains all the atom names and ...
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28 views

Goodness-of-fit test to use for weighted data

Hello. I'm working on a AP stats project, but since what I'm doing is beyond the scope of what we do in class (i.e. learn how to use a calculator), I think it's safe to say this isn't a homework ...
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41 views

Degrees of freedom for chi-squared test for a random variable potentially from a mixture generation

I recently posted Multinomial mixture model but got no answer. Hence I take the liberty to present what I came up with on my own and a follow up question: I have two processes which generate a series ...
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10 views

How to define shape and scale parameters of selection for testing selection on Pearson Criterion?

I have selection generated by my program. I need to test null hypothesis about accordance to Weibull distribution using Pearson criterion. I stuck on defining alpha(shape) and lambda(scale) parameters ...
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23 views

Hypothesis testing for skewed data

I have a skewed distributed data in the form of contingency table. Which hypothesis test should i use in this case ? Will chi-square work for skewed distribution ? Any pointers on comparison of ...
2
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1answer
51 views

Chi square 2x3 table - Genotypes are related to disease?

I want to conduct a Chi square test of independence. I have three different genotypes (CC/CG/GG, independent variable) and "health conditions" (outcomes) which is basically a patient group with a ...
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12 views

Allocation of product with ANOVA or something else (?) in R - what direction and tests to use?

Assuming a very simplified view of my data looks like this: ...
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31 views

model comparison: chi2 vs. AIC (and BIC)

I've been using the approach from Appendix A from this paper. It states that if I have two fits with $\chi^2$ values $\chi^2_1(\nu_1)$ and $\chi^2_2(\nu_2)$ ($\nu$ - degree of freedom), then their ...
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2answers
81 views

Chi Square independence test for continuous measure (not counts)

Suppose I do A/B testing and I collect many observations. An observation is the visit of a client into the store. I collect if the client bought something, the value of the eventual purchase, if the ...
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1answer
37 views

What statistical test would be appropiate for determining the preferences of lottery players?

I'm trying to conduct a simple study: to find out if there is a significant relationship between the time perspective of a person and his propensity to buy lottery. So to keep it simple, my ...
0
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1answer
26 views

chi squared test for data observed and theoretical between 0 and 1

I am doing some data analysis for a project and need to make a fit of the data to a line using least squares. Then i need to evaluate the goodness of fit of my data to this line using chi squared. ...
2
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1answer
58 views

Fisher's exact test vs chi-squared

I've been trying to figure out the correct way to calculate the p-value for my data. I originally created a simulation that randomly selected numbers that were greater than or less than a certain ...
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30 views

Fitting a GLM for binomial data in R

I am an R beginner and out of my depth! I am trying to build a model to analyse data regarding fertility in 2 populations of different levels of sexual selection(M and P), both of which have undergone ...
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39 views

Knuth rule for number of bins of a histogram vs. chi2 fitting

I try to make a histogram and then fit some distribution to it by means of chi2. The Knuth rule (I have some bimodal cases so I'm not using Freedman-Diaconis or Scott) gives me the following histogram ...
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2answers
78 views

Is chi-squared valid in this scenario?

I'd like to know whether I am misusing Pearson's chi-squared test. And if so, what should I be doing instead. I've a game-playing program, a "bot", for a zero-sum two-player game. To improve it, many ...
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3answers
79 views

Chi-squared vs ANOVA test

My study consists of three treatments. One treatment group has 8 people and the other two 11. Each person in the treatment group received three questions and I want to compare how many they answered ...
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22 views

When used for feature selection, does the chi-squared test require the features to be nonnegative?

scikit-learn says chi squared test used for feature selection in classification problems and implemented by sklearn.feature_selection.chi2 requires the feature ...
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0answers
81 views

chi square for trend - SPSS

I have followed fourth-year university students for ten years, recording their attitudes to a particular lecture. The outcome is binary (good-bad). I have 10 rows and 2 columns, meaning year and ...
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0answers
20 views

Clarification on null hypothesis, w.r.t pchisq() function in R, and the tail argument

I'm looking at two functions for testing goodness of fit for a logit regression model (glm). Firstly anova(), used as ...
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50 views

What kind of feature selection can Chi square test be used for?

Here I am asking about what others commonly do to use chi squared test for feature selection wrt outcome in supervised learning. If I understand correctly, do they test the independence between ...
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29 views

User Study Setup: Correct selection of tasks

I'm struggling with the problem to design a formally correct user study. I have the following circumstances: I want users to assess the (subjective) usefulness of a -so called- trail result. That ...
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43 views

Transform sum of gamma distribution to chi square distribution

Let's say that I have a random sample $Y_1, Y_2, \dots, Y_n \sim\Gamma(\alpha, \theta)$. I can work out using the moment generating function that the distribution of $\sum Y_i$ is $\Gamma(n\alpha, ...
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42 views

How do I solve this problem? Novice here

Here's the problem. I work for a transportation company and we're trying to prove the following hypothesis: Drivers are allowing passengers on the vessel without taking taking their paper boarding ...
4
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1answer
34 views

Normal with mean unequal to zero squared

It is a well-known fact that if $x_i \sim N(0,1), i = 1, \dots, n$, that then for $\nu \in \{1=1,\dots, n\}$ it holds that $\sum_{i=1}^\nu x_i^2 \sim \chi^2(\nu)$ I was wondering what now would ...
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1answer
38 views

Minimal sufficiency and UMVUE in a pseudo-Normal distribution

I already asked a (stupid) question about this problem here thinking I wouldn't have problems to continue it but I was pretty wrong. I'm finding several more problems trying to solve it. I'll try to ...
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15 views

Degrees of Freedom for Inhomogeneous Markov Chains

Suppose I am given a time-inhomogeneous Markov chain. For simplicity, let's assume we have 5 (time) positions, and 4 states (A,B,C,D). How can I compute the degrees of freedom for a first order model ...