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

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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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18 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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35 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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22 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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6 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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58 views

Multivariate Normal Distributions & chi-squared

With a table of data with multiple variables (lets say 2 for ease) and multiple samples how can one calculate the chi-squared test statistic? That is, given $x\sim N(\mu,\Sigma)$, the chi-square ...
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26 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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272 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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25 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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19 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
51 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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15 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
41 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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28 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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11 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
42 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
302 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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653 views

What is this equation (pictured) called?

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

Significance of proportions in clustered data

I have data for multiple homes, each of which spends a certain amount of time in Condition 1 and then a certain amount of time in Condition 2. While in these two conditions, there are a variable ...
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1answer
34 views

Testing small proportions

My data is made up of 4 groups, each with a large and identical sample size of 20,000. The number of successes in each group is fairly small: ...
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17 views

Histogram of noncentral chi-square variable shoots up when the number of histogram cells increases

Consider the random variable defined by: $$y=-8x+108$$ where $x$ follow a non-central chi-square distribution with 1 degree of freedom and a non-centrality parameter equal to 3.5, $x \sim ...
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which random variable is a rescaled non-central $\chi^2$ random variable?

Probably simple question. Consider the Cox-Ingersoll-Ross model (1985) model for interest rates $$ dr = k(\theta - r)dt + \sigma \sqrt{r}dz $$ Then it is known in closed form the conditional pdf ...
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1answer
30 views

Problem with Application of Pearson's Chi-Squared test

I'm using Pearson's chi-squared test to to compare the knowledge of two independent groups on knowledge about contact lens. But the number of respondents in group A is n = 200 and the number of ...
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28 views

Fisher exact test (9x2) vs pearson chi-square (SPSS)

I am doing one analysis where I have 9 different conditions and only two options as outcome. I have done a pearson chi-square test, and in some of the cases I violated the assumption that expected ...
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28 views

Pair-wise comparisons for chi square test SPSS?

How do you see pair-wise comparisons for chi square test SPSS? I have 4 groups and one variable and want to see all the significant pair-wise comparisons.
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1answer
38 views

Chi-Squared significance test for stopping criteria in decision tree

Going through the paper of BFTree(Best First Decision Tree) from (Haijian Shi (2007). Best-first decision tree learning. Hamilton, NZ). I read for pre-pruning do a local attribute selection. And the ...
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345 views

What distribution does Fisher's exact test assume?

In my work I have seen several uses of Fisher's exact test, and I was wondering how well it fits my data. Looking at several sources I understood how to calculate the statistic, but never saw a clear ...
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31 views

What statistical technique could I use to see if gender effect exists in this scenario?

Suppose I give 6 short stories (of word length varying from 200 to 400),and ask N=100 students about which one (e.g., story #1, #2,..., #6) is their favorite story (see below table). Some data are ...
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21 views

Is it okay to convert binary data to percentage data?

I have a within-groups study with 4 groups (400+ users). Each user answered 10 questions for each group. The answers were scored as right/wrong (1/0). Can the percentage correct for each user/group be ...
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1answer
25 views

CFA chi-square value ordinal variables

For my thesis I need to know how the chi-square value is computed with a CFA for ordinal variables, using DWLS (preferably in R). I know that for continuous variables the chi-square is computed in the ...
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1answer
129 views

Does the birth date of professional boxers matter? Prove/disprove what an astrologer might predict

As a followup to my question about the birth month of boxers, I am posing the fundamental question along with my hypothesis (testing if there is any truth to a conclusion an astrologer might make): ...
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1answer
46 views

A reference for Pearson's chi-squared testing

I am wondering if there is a reference for the Pearson's chi-squared test suitable for technically-sophisticated audience that simply presents when the test (in its various forms) is appropriate and ...
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1answer
17 views

How to combine clinical variables?

I am dealing with several clinically used variables that are not linked to each others. Those variables are correlated to worsened prognosis (some are numeral and asymmetric, therefore correlations ...
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41 views

Post-hoc Chi Square Test for Pairwise Comparison of 3 Groups

I am trying to do something that in my mind is probably simple and I'm probably just blanking on it. I am using Stata to compare 3 groups on a categorical variable. So, as an example, I would be ...
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72 views

Converting Chi Square Adjusted Residuals to p values

I am running a chi squared analysis in SPSS on a 5 x 2 contingency table. The overall chi square p value was < 0.0005, so I ran post hoc tests (adjusted standardized residuals on the individual ...
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22 views

Confidence intervals for chi square goodness of fit

I'm having trouble figuring this out. I know that you calculate the confidence interval same as you would for a proportion, $p_i= P \pm 1.96 \sqrt{(P(1-P))/N}$, but in my notes it says: ...
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1answer
26 views

How to interpret confidence interval with accuracy phrase

Upon reading a peer reviewed article, I found this: A Chi-square test shows that the demographic characteristics of the sample represent Toyota GB’s hybrid customers (data obtained from the New ...
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chi-squared test vs fisher's test vs … => highly unbalanced length frequency data

I would like to statistically verify if two distributions are identical. Basically, the first distribution is a length frequency distribution from a large population ("population"). The second is the ...
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1answer
73 views

Chisquared on categorical data or a Wilcoxon test on the counts hereof?

This question is related to a question I had in R on SO here The background of my question is fairly simple. I was given two "databases" in the form of data.frames ...
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45 views

Finding sampling distribution of normal MLE and likelihood

I'm reviewing old exams in preparation for a statistics final, and I'm stuck on a particular question: Suppose that you have n independent random variables $Y_i$, with each distributed normal with ...
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2answers
71 views

How to determine whether a variable is significant using Pr (>Chi) and Df?

I wonder how can I determine whether a variable is significant using Pr (>Chi) and Df? Take following ANOVA table as an example, I know variable type is ...
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36 views

the Chi-squared distribution and Mahalanobis

I'm doing some simulations in C++ and OpenGL (2D and 3D) for navigating a robot in unknown environment known as SLAM. I'm using Extended Kalman filter as an optimal estimator. In SLAM problem, once ...
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30 views

I cannot use Fisher or Chisq test. What now?

I am trying to understand if there is a variance in the counts regarding two categorical variables. Gender Profession Salary F Teacher 12 M Teacher ...
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2answers
26 views

Determining unusual binomial results from a sub-population

If I have a population of 1948 students with a success rate of .154 (301 successes) and I break the 1948 students into their respective majors, how to I determine if the sub-population success rate is ...
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62 views

How to evaluate similarity of datasets based on summary data?

I have summary data that I want to compare to my own data. For the summary data I do not have access to the underlying data, however, I know the percentiles as shown below (A). I also calculated ...
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17 views

Are my data normal? chi-squared for goodness of fit [duplicate]

I have been tasked with determining if my observed data follow a normal distribution. With 119 observations (continuous data from -4 to 4), I was able to create a histogram with 25 bins, and upon ...
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How to determine if these values are different?

I don't have much stats background (I am a programmer) but want to learn more. I have five long columns of numbers that represent conversion rates (ex. how many successes vs. how many attempts) for 5 ...
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87 views

Hypothesis testing using R

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