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

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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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22 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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7 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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19 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 ...
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1answer
34 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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9 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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26 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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41 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
34 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 ...
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1answer
23 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. ...
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1answer
44 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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23 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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33 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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69 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
57 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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18 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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30 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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14 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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30 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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25 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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41 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 ...
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1answer
29 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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29 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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14 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 ...
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Probability that one sum of squared standard normals is greater than a constant times another such sum

Let $Y_1,Y_2,..., Y_n$ $i.i.d$ $\mathcal{N}(0,\sigma^2)$ random variables and $n>4$. Find the probability $\mathbb{P}\{Y_3^2 + Y_4^2+ ... + Y_n^2 \geq \alpha ( Y_1^2 + Y_2^2)\}$ for $\alpha ...
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30 views

Fisher's exact test statistic?

When reporting the results from a Fisher's exact test, do I just report it like (fishers exact, p = .02) or is there a test statistic for Fisher's exact test?
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33 views

what is the definition of expected counts in chi square tests?

Just wondering whether anyone could define expected counts in regards to a chi square test. Thanks in advance!
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30 views

Which test? Chi-square, non-parametric or Poisson Regression..? What species is the most frequently observed

I'm reposting my question based on previous comments received. The problem: 10 x 100m sections of shoreline have been sampled to determine if one species is the most frequently observed species ...
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41 views

Is the frequency of one observation greater than the frequency of others

Suppose I have 10 bags of M&M's. I count the number of red, blue, green and brown M&M's in each bag. I want to know if there are more red M&M's than other M&M's in the bags and if this ...
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5 views

Finding the differences for nominal data when each participant contributes to more than one cell in the frequency table?

Finding the differences for nominal data when each participant contributes to more than one cell in the frequency table. The point is that I don't have paired nominal data as it is in repeated ...
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1answer
33 views

Which statistical analysis test can I use when the instances in the sample is not independent?

I am wondering if the data I have here is eligible to do statistical analysis. The problem is: I collected data from 20 person with age less than 20 (Group A), from 21 person with age large than 30 ...
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27 views

Chi-square test for interaction

I want to look at the interaction between two independent variables on a binary dependent variable. I can't use a binary logistic regression because I have a small sample size. Can I do this using a ...
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15 views

Determining parameters for distribution of standard deviations

I have a database of 10-star movie ratings (similar to IMDB), with a large number of movies and an also large number of ratings for each movie. For each movie I have computed the mean and stddev of ...
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3answers
67 views

Highly significant Pearson's chi-squared test (goodness of fit) when observed & expected are very close

I have two arrays that I would like to do a Pearson's chi-squared test (goodness of fit). I want to test whether or not there is a significant difference between the expected and observed results. ...
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11 views

How to calculate non centrality parameter?

Suppose $Y\sim N_p(\mu,\sigma^2I_p)$. Let $A$ be a symmetric idempotent matrix. I want to show $Y^{T}AY$ follows a chi-sq distribution with some non centrality parameter. Suppose ...
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50 views

$\chi^2 $ of multidimensional data

I want to test if two observations of nominal data accord to the same distribution. I am using the chi squared statistics to perform a chi squared homogeneity test and normalize the result with ...
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1answer
70 views

How to to find and evaluate optimal discretization for continuous variable with $\chi^2$ criterion?

I have a data set with continuous variable and a binary target variable (0 and 1). I need to discretize the continuous variables (for logistic regression) with respect to the target variable and ...
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1answer
57 views

How to interpret the residual colors on a mosaic plot?

This is a mosaic plot of contingency table dataset HairEyeColor described here. How do I interpret the colors representing residuals? What is the difference ...
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What test is appropriate for my data set?

So my data is on feedback students receive during their 4 years at university. I sent out a questionnaire and there are 23 questions in total, each question is looking at the perception and value of ...
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2answers
51 views

Does color affect purchase decisions across items?

My question relates to Determine if being on honor roll gives an advantage in being assigned to the math class (I've seen similar questions involving hits on a webpage) which I believe should be ...
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24 views

How is p-value performing as a measure of association?

It's known that Cramér's V (Chisq adjusted for table dimension and sample size) is a good measure of strength association. But what about the p-value? P-value (as a probability of the numbers we have ...
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1answer
44 views

Determining $\chi^2 $ for Cramer's $\phi $

I intend to determine Cramer's $\phi$ for two contingency tables of the following form: ...
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1answer
27 views

Distribution of sum of mean squared errors - weighted sum of chi squared distributed variables

Suppose $X,Y$ are independent chi-squared distributed random variables with $m,n$ degrees of freedom, $X \sim \chi^2(m)$ and $Y \sim \chi^2(n)$. What is the distribution of $$ Z = \frac{1}{m} X + ...
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21 views

Phi correlation for multiple cells [closed]

I have this table for chi-square in R: x <- matrix(c(23,22,10,14,11,12),ncol=3) phi(x) this is a 3 by 2 table and thus phi correlation won't work here, can ...
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13 views

Differences in variables constructed by counting.

I have constructed a frequency variable from counting events of certain magnitude (e.g, 1,2,3...) from a time dependent experiment with animals. I have two groups (Trained vs Control) and two phases ...
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112 views

Mahalanobis Distances Critical Values (Chi-Squared?)

Say I work out the mahalanobis distance 'D' to measure the separation between two objects (which aren't normally distributed). Say I now want to use 'D' against some critical values to decide if it's ...
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61 views

Chi-square: naïve compensation for low frequencies

As far as I understood it, chi-square provides a measure for determining the similarity of the expected and observed (empirical and theoretical) distributions of nominal variables. It can be employed, ...