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

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Testing Whether a Binomial Distribution Fits Data

I have a sample from a discrete distribution as such: Type: 0 1 2 3 4 5 Occurrences: 88 12 52 43 21 5 My task is to test whether ...
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16 views

Can the chi-squared be used to test monthly means for two time series?

Can chi-squared test be applied to compare two continuous random variables but where instead of counts we split samples into groups and into cells of the table we put means for groups? In our case we ...
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21 views

What is degrees of freedom for chi-square for my scenario? [on hold]

I have observed frequencies is as below: observed[-97, -87, -83 -103, -87] and expected frequencies as below : expected[-95, -87, -85, -101, -97] chi-square = abs(((-97-95)^2/-95) + ...
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9 views

Fisher's exact test for 3x5 contingency table in R with post-hoc? Consistently with using Fisher or Chi-squared?

I'm struggling with some (relatively simple) stats questions for some work I'm doing in R, and can't seem to find answers online... I have a factorial response variable of habitat type of a species ...
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32 views

Why is normality assumption so important (even for large N) for Chi-square test for the Variance

In my textbook i found the note that for a Chi-square test ($\chi = \frac{(n-1) \cdot s'^2}{\sigma^2}$) the assumption of a normal distribution in the population is very important - and much more ...
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62 views

Optimizing parameter estimates by minimizing chi^2 in iterative procedure

I need to minimize my Chi^2 (bottom-left in figure 1) by adjusting parameter-values in a MLE-procedure (or something alike). The chi^2 (red) is a goodness-of-fit measure. It expresses how well the ...
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11 views

Chi square test of independence with multivariate nominal data

I used a list-type open-ended question to collect responses, in which respondents can list up to 6 items. After coding the items, I have the multivariate nominal data. I want to check if my IV ...
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1answer
35 views

Chi-square test on a sample from population having an unequal distribution

I got a sample with an unequal gender distribution ($30$ males to $200$ female). This distribution is quite "representative" for the population the sample is taken from. Nevertheless, in a paper, ...
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35 views

Uncorrelating correlated $\chi^2$ distribution

This question is related to my previous question in here So I was trying to simulate correlated $\chi^2(1)$ random variables given the desired co-variance matrix. However, it seems like the only ...
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1answer
18 views

Outliers and chi-squared goodness of fit

Do outliers lead chi-squared tests of goodness of fit to fail?
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10 views

Comparing proportion of categories in samples of different sizes

Maybe this is a very simple procedure, but I have been trying to find the appropriate method and I am getting confused. I have data from two different surveys. In the first survey (s1) there were ...
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1answer
31 views

Chi squared goodness of fit test

I have a dataset and I want to show that it has lognormal distribution by using estimated logmu and logsd of it by MLE. I have read about making dat into bins by using predetermined intervals, but I ...
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1answer
44 views

Power analysis on chi-squared test with low cell counts

I am hoping to perform a chi-square test of independence on data in a 2x2 contingency table with the following values: ...
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10 views

Goodness-of-fit test by Pearson's chi-squared test for bimodal normal distribution

Consider I have estimated the following parameters for two modes inside a vector of numbers: m1,s1 m2,s2 m is mean s is standard deviation I want to use ...
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32 views

Should I split my independent variable into 2 groups?

I want to study if atheists/non-believers are having a harder time gaining results from 12-step facilitation treatment for alcohol dependence. My hypothesis is that a higher degree of belief in ...
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12 views

Taking into account population size differences in chi-squared test

I have a group of patients who live in London. They come from the 33 London local authorities and I want to know whether there is any significant variation in where they live. In other words, I want ...
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22 views

How to test a difference in proportions… over many iterations?

I'd like to compare results between two set-ups (let's call them A & B) whose outputs are the proportions of a quantity allocated to three options let's call them (1,2 & 3). The null is that ...
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9 views

What statistical instrument can we use for Intrinsic Motivation Inventory?

We had an experimental research about motivation. We used IMI (Intrinsic Motivation Inventory) as our instrument. The IMI consists of four sublevels/category. I already calculated the average for each ...
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10 views

analyzing categorial data from mixed design

I have the following experiment setup: N participants go each through each condition C1, C2...C7. The outcome of each condition is either pass or fail, so a binary outcome. The data can be readily ...
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1answer
42 views

3 values ordinal variable: Mann-Whitney or Chi-squared?

I have an ordinal variable which assumes only 3 values. I need to do a comparison between 2 treatments. I used Mann-Whitney test, since is an ordinal. My "p-value" is quite high (0.9388) which is ...
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26 views

Pearson's chi-squared test with proportions?

I'm trying to test if a dataset follows Benford's Law (https://en.wikipedia.org/wiki/Benford%27s_law), which basically says how many values in a data set we'd expect to have a first significant digit ...
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1answer
41 views

chi square tests & graphing

I was wondering what the appropriate test would be for comparing the results of two chi-square tests. For example: I have one experiment where I determined if there was a significant difference in ...
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31 views

calculating the statistical significance of overrepresentation of a substring in a string

I have a sequence of characters in a long string like this 'ATCGCGCGCGATCGACGCGTACGTCGGATCTA.....' And I know that for example the substring 'ATCG' has been ...
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1answer
108 views

Asymptotic distribution of $\chi^2_{(1)}$

Let $z_1,\dots,z_n$ be i.i.d. $\chi^2$ with $k$ degrees of freedom (Neither $n$ or $k$ are fixed). Is anything known about the distribution of $\min_i(z_i)$ asymptotically, when say $n/k\to ...
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1answer
31 views

Likeness of brands using tweets - is Chi-square appropriate?

I'm trying to determine if brand x is more similar to brand y or brand z using tweets. I have a data set for the words that occurred in each brand's tweets, and I'm considering using the chi-square ...
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1answer
27 views

First order statistic of folded normal

Are there any good approximations or tail bounds for the first-order statistic of the folded normal, or the closely related chi-square distribution with $k$ degrees of freedom? It seems that the ...
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2answers
67 views

Is the chi-squared test appropriate with many small counts in a 5x2 table?

I have two sample populations, A, and B, which are independent. ...
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52 views

Why not use always a binomial exact test to compare two proportions instead of chi square?

I am trying to figure out what test I should use in the following scenario: I know that there is a lot of room for improvement in a specific area at work - being extremely critical, let's say that ...
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4 views

Analysis of possibly correlated small sample data

I'm doing an experiment where I'm imaging 3 groups of 5 rabbits (total = 15 rabbits) using 4 different machines at 4 different anatomical locations to see if a radio-opaque material is visible in all ...
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45 views

SPSS chi-square output interpretation

Sorry for the dumb question, I need some help with the interpretation of the spss chi-square test outcome. Basically I have two variables: the first one is a binary variable which takes value 1 if a ...
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18 views

How to Rank the Effects (Coefficients) of a Categorical Variable

I have a categorical variable, 'Ethnicity' with 12 levels, and an output variable 'has_condition' stating whether a particular subject had a particular genetic condition (1 means favorable, 0 means ...
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1answer
26 views

Chi Square distribution with degree of freedom 3

For X following a Chi-square distribution with degree of freedom m = 3, I want to compute P(1 < X < 4) Would it be, ...
4
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1answer
68 views

Post-hoc test for chi-square goodness-of-fit test

I'm conducting a chi-square goodness-of-fit (GOF) test with three categories and specifically want to test the null that the population proportions in each category are equal (i.e., the proportion is ...
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23 views

support vectors in text analytics

i am beginning to harness scikit's svm to perform some news analytics. While going through their tutorials they perform a classification (using linear SVM) on a dataset called 20 news group. I chose 4 ...
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48 views

Understanding the background to chi-square test for tables

I have moved this question from the maths educators site on their recommendation. I have read previous questions on this site and don't quite understand fully and hopefully my question is sufficiently ...
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1answer
32 views

Asymptotic chi square tables?

I just need to calculate the value of the right hand side of the test statistic which is an asymptotic chi square distribution. How can I find those values? All I have is the normal chi square ...
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10 views

Using R, are these methods valid for determining relationships among Likert scale responses (in different columns) that are nonparametric

I’ve been analyzing Likert scale and was hoping to get some guidance on the methods. The problem with Likert data, of course, is the controversy over whether to analyze it as ordinal or interval ...
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1answer
33 views

chi-squared / Fisher's exact test with incomplete data for contingency table

I have a treatment group (n=42) and a control group (N=12). From this this, 13 used in the treatment HTN drugs and 4 people in control group used HTN drugs. How should the contingency table be set ...
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2answers
325 views

Is “Confidence Level” just 1 minus P-Value?

If the results of a Chi-Square test give a P-Value of 0.01 then can we say that the confidence level in their being a difference is (1-0.01) = 99% confidence. Background. We are conducting website ...
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1answer
36 views

Chi-Square test: one-sided implementation?

I need to compare two samples and I would like to know if the distribution of the first stochastically dominates that of the second one. I'm not sure whether with the Chi-Square test I can verify ...
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20 views

Is it possible to incorporate on/off cycles into a product's failure rate prediction along with its field failure rate and test data?

If I have a electronic module whose failure rate I am calculating using the chiinv() function in Excel, and the following data available to me: -test failures and test hours for the module and the ...
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1answer
66 views

Chi-square test p-value = 1

I am attempting to use the chi-square test as a goodness-of-fitness test in R, but I keep getting a p-value = 1. I expect a high p-value, but less than one. Can anyone point out what error I might be ...
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21 views

Test if 2 samples are taken from the same population (multi-dimensional data) - worked example

I'm looking to learn (not just apply) how to test is two samples are drawn from a single population. The data I'm likely to apply this to is multi-dimensional so that's my target. Can anyone give me a ...
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5 views

What's the best way to demonstrate differences in these means/totals?

With some co-authors, I coded 200 video game reviews based on whether they mentioned any of nine different game elements. We now have the total number of times that each game element showed up in ...
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1answer
92 views

Post Hoc Pair-Wise Comparisons for the Chi-Square Test of Homogeneity of Proportions

I am looking for a "Post Hoc Pair-Wise Comparisons for the Chi-Square Test of Homogeneity of Proportions" (or an equivalent of it) Which is described here: ...
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33 views

Test of Independence Between Two Nominal Variables With Many Levels Each

I am looking to test whether there is a significant relationship between two nominal variables, one which has 100 levels and the other with 10 levels. I initially considered doing a $\chi^2$ test of ...
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15 views

Chi square test and comparisons within this

I'm running chi square on a set of data that consists of frequency, question type, and participant group. I have an overall significant statistic but want to get p values for each question type across ...
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2answers
45 views

Output of chisq.test in r

I have a question regarding the below output from a chi-squares test, which I find to be confusing and contrary to my expected results - my chi-squared value is infinity here :) I have two questions ...
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1answer
307 views

How to detect random clicks on a page?

I have been tasked with detecting if a bot is clicking randomly around a web page. I was thinking of splitting up the web page into 20 by 20 pixel squares, and then assigning each click to a square ...
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664 views

What is this equation (pictured) called?

Could someone provide some Google-able words for this equation? $$Q_{\chi^2,d} = \left[2^{d/2}\Gamma\left(\frac{d}{2}\right)\right]^{-1}\int_{\chi^2}^\infty (t)^{\frac{d}{2}-1}e^{-\frac{t}{2}}dt$$ ...