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

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3
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34 views

Chi square test in a contigency table with sampling zeroes

im trying to estimate if an association exists between two variables in a 7x5 contingency table (the type of prosthesis with the type of complication). The table contains a lot of sampling zeroes and ...
0
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0answers
16 views

SCORE METHODS CONFRONT

I would like your opinion. my data is score (before and after therapy) on radiographs made with x-ray instrument and score based on the judgment of the doctor. I thought I create a new variable which ...
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10 views

Confidence & conclusion in rare event analysis

I am looking at the http://www.nejm.org/doi/full/10.1056/NEJMoa021134 paper and don't understand how they made their conclusions. According to the data in Table 1 they analyzed 440655 vaccinated ...
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1answer
12 views

Chi squared test sample size

I'm trying to figure out if there's a difference across the main capitals in Europe and the voting preference of their inhabitants for extreme right political parties. So far I have categorized all ...
0
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0answers
7 views

Significance test for yearly collected average data

I have data from a random survey that is collected every year. One of the variables are the expenditures per person for health care spent in the corresponding year. Another variable is the percentage ...
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2answers
49 views

How to proceed with chi square test in R if one line has zeros?

I am trying to program with R. My categorical data is in a table of 5*5. However, the 5th line has only zeros. When I run the chi square test in a software program, it returns the result INVALID. But ...
3
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1answer
28 views

Chi-square test of equality for 25th and 75th percentile

I would like to examine the equality of the 25th and 75th percentile between two groups. One way would be to apply Mood's test adapted to the 25th percentile (and then to the 75th): Construct the ...
0
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1answer
23 views

Fisher and chi-squared assumptions/limitations not met

Fisher exact test is said to be used with a total sample (n) < 1000, whereas chi-squared test should be used when each category (/cell in a contingency table) >=5. What if you have an mxn ...
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0answers
18 views

Independence test for three categorical variable

I want to know if my use of the $\chi^2$ test of independence is valid. I have three binary categorical variables, $X,Y,Z$, and I want to test the following hypothesis. If you are in the group $X = ...
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0answers
17 views

Why does the test statistic from Pearson's chi-squared test for independence have a chi-squared distribution?

Why does Pearson's chi-squared test for independence have a chi-squared distribution? I can see that the numerator is squared, but doesn't the division by $E_i$ affect the distribution? $$ \chi^2 = ...
0
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1answer
28 views

Difference between logistic regression and chi-square for analysis with no covariates?

I have a binary response variable (0s and 1s), the distribution of which that I want to compare to chance. I understand I could use logistic regression or a chi-square test to do this and that these ...
0
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1answer
14 views

Is a Fisher exact test for count data appropriate with an ordered factor?

I have the following contingency table: ...
1
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0answers
14 views

Finding discrepancies in distances between random variable samples

There are $N$ independent and unknown points $p_i$, $q_i \in \mathbb{R}^3$, $i \in [1, N]$. I want to find if the pairwise squared Euclidean distance of each $i$ pair is the same for all of them, or ...
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0answers
12 views

Correct equation for Breslow-Day statistic in homogeneity test of odds ratio

In Statistical Methods of Cancer Research; Volume 1 - The analysis of case-control studies the authors Breslow and Day derive a statistic to test for the homogeneity of combining strata into an odds ...
2
votes
1answer
72 views

Why is a low (<1) chi-square measure unlikely when degress of freedom are high?

If the chi-square measures variability, where 0 is no variability and a very small measure is no variability, shouldn't all chi-square distributions be shaped like the dof-1 distribution, where the ...
0
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0answers
35 views

p-value interpretation of Jonckheere Terpstra:one-sided or two-sided

I am using the Jonckheere-Terpstra test in order to validate the pooled t-test results. Basically, I like the JT test because of its non-parametric nature. Basically, I am now trying to understand ...
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0answers
16 views

Combining independent observables for the same quantity, how to check independence

Let's assume we have a set of observations $\{x_i\}$ of a physical quantity $x$. We have a model $x=X(y)$, where $y$ is a free parameter. Let's assume that we have two distinct observables, $f(x)$ and ...
0
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0answers
6 views

One Response Value Fails for Proportional Odds Assumptions

I am analyzing placement scores on the response of students' grades for various courses. I have used a Chi-Sq test with the likelihood ratio to check the proportional odds assumption. For one of the ...
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0answers
27 views

How to evaluate the combined effect of 2 variables?

I'm trying to analyse the effect of smoking on health. The health variable is binary(healthy or not) but there are 2 different exposures to smoking(active=variable A and passive=variable B). Variable ...
0
votes
1answer
14 views

Does the sample size for the dependent variable should be the same for all the values of the independent variable in Peason Chi-square?

I have a question about the sample size when using chi-square test of independence or multinomial logistic regression. I would if you provide me with your feedback since I search a lot and I could not ...
0
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0answers
6 views

Difference between expected spending and spending observed. What kind of statistical analysis should I apply?

I would like some advice from you about what kind of statistical analysis I could do about that data. My case is as follows: According to a research I have the information that the financial health ...
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0answers
33 views

Multiple Hypothesis Testing with Categorical Variables and Alternatives

Suppose we have a variable $Y_i$ which is a binary categorical variable, and we have a variables: $X_{i,1}$, $X_{i,2}$, ....$X_{i,n}$ ($i=1,2,....N$ where $N$ is sample size, and $n$ is the number of ...
5
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1answer
60 views

Mode of the $ \chi^2 $ distribution

I've been studying a statistics textbook that makes a claim that the $ \chi^2 $ distribution with $ k $ degrees of freedom has a mode at $ k - 2 $ without proof. (Wikipedia seems to agree) Why is ...
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0answers
24 views

Calculating p-value based on Chi-Square vs Z-Test incl Standard Error

I have been testing the significance levels for my various a/b tests. Degree of freedom is 1 so there's not a lot of complications here. So far I've been calculating my results using Chi-Squared ...
3
votes
1answer
38 views

Help with intuition about Chi-Squared distribution and its relation to Normal Distribution

At $\alpha = 0.05$, the significance cutoff of a Chi-squared distribution with 1 df is approximately 3.84, and that if we take the square root of 3.84, it's approximately 1.96, which is the 97.5 ...
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9 views

Should I use an Odds Ratio or a Likelihood Ratio to report prevalence of x in a Case-Control study?

I am trying to report the prevalence data for a case control study. I first ran a $\chi^2$ test on a 2x2 table of the prevalence data. I got a $\chi^2$ and Likelihood ratio result in SPSS. It ...
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0answers
9 views

How does Weka chiSquaredAttributeEval generates single attribute selection list while Chi Square itself is class based?

I have implemented my own Chi-Square ranker in C# however the example i found on the internet shows that Chi-Square ranks the each attribute within its class However Weka generates attributes as a ...
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0answers
19 views

Reverse solve chi-squre statistic to find number of observations

I am trying to prove that two proportions are equal with 95% confidence. I have a total population Tp (10000), and wins in that population of Wp (2000). My sample size is Ts (1500). I need to solve ...
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1answer
98 views

Independence of two categorical variables & chi-square

I have data as follows: ...
0
votes
0answers
8 views

Error estimation in a two parameter non-linear model

With a dataset of $N = 26$ values for $n = 7$ different species (some species with 3-4 data points, one or two with 5)I've found the average value $y_i$ and standard deviation $\sigma _i$ for the $n$ ...
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0answers
26 views

How to use permutation test to create null distribution for categorical data?

Consider a population of 1,000,000 individuals. I have examined them all and identified 1000 samples which I believe are not like others. To confirm this I analyzed the 1000 sample regarding one ...
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0answers
10 views

“Goodness for fit Chi” test on point pattern

Apologies, I have a few question today I hope there is no limit to how much I can ask here before you start billing me :) What is the meaning of Goodness for fit Chi-sqaure test? From the wikipedia ...
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1answer
46 views

Are Pearson test and Chi-square test the same

I'm a bit confused with Chi-square and Pearson. I know Chi-square is: Chi-square = E (sum of) (Oi - Ei)-square / Ei What would the Pearson formula be if it is different? I don't think it is ...
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0answers
7 views

How to evaluate the quality of Bayesian network sampling?

I have generated a sample from a Bayesian network by applying Forward Sampling. I learn the parameters of the network (the same structure) from this sample so as to evaluate the quality of the sample ...
0
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0answers
21 views

Scaled vs. unscaled Chi-square statistic in CFA / GRM fit evaluation

I generally want to assess the fit of a CFA model with ordered categorical indicators (the graded response model, GRM). There are two versions of this model, the normal-ogive GRM (ordered CFA with ...
0
votes
1answer
35 views

chi-squared test of two row table while calculate cells in row 2 from total n of row 1- is this valid to do?

I have count-data of patients with an event which occurred on different days in the week. For example: ...
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0answers
20 views

How to apply Chi Squared test according to this Simulation?

I would like to introduce the following scenario to better clarify my question: Let's say that one day while doing research on the city of Villy God has appeared to me and told me that city there are ...
0
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0answers
34 views

How to compare groups when the control group is 100 times larger than the group in question?

I am working with NIS data which are basically a 20% sample of all in-hospital admissions in the US every year. I have small group of cases that carry diagnosis "X" in their record and overall the ...
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0answers
24 views

Is chi-squared an appropriate test in this scenario?

I have tested two separate testing tools on a sample of people. Each tool splits people into three separate categories. My questions are: 1) Is there any difference between the allocation of people ...
2
votes
0answers
38 views

Chi-squared goodness-of-fit test and conditional probability distribution

I have three discrete variables, let's say $A, B,$ and $C$. The number of possible values of $A$ is 3, and $B$ and $C$ take binary values. I also know the probability distributions, $Pr(A | B, C)$, ...
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0answers
40 views

Chi-square testing with demographic data viable to compensate non-response bias?

(Hello CrossValidated, first poster here, so please have mercy with any transgressions of mine!) For my thesis, I am currently researching the correlation between stance to organizational change and ...
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0answers
11 views

Orientation of point dataset

Looking at the well-known Pine dataset (Numata, 1961) it appears in different articles in different orientations. 1983 Digggle: Then sometimes appears rotated: Or even flipped: Other than ...
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0answers
13 views

Comparing count groups/hisotgrams with different bins

I'm looking at clustering techinques for which I have a ground truth. From the ground truth I can extract the cardinality (size) of clusters and I would like to test how well different methods can ...
0
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0answers
62 views

The statistical significance of a single regression model

I currently have a neural network regressor which is tested on 45 samples. The TRUE response variable has a mean of $\mu$ and standard deviation of $\sigma$. What I would like to do now is test ...
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0answers
15 views

Can I use Chi squared to compare proportions?

So I have these 3 animals, and they spend time in 5 different habitats (sum of time spend is 1). ...
1
vote
1answer
53 views

Which Test to check relationship between age (ordinal independent variable) and nominal variable (type of car)

I have two variables age and type of car bought. Age is in groups. Eg. $<25$, $26-35$, $36-45$, $46-55$, $>55$. Car is 1. American, 2. ...
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0answers
6 views

Dichotomous independent and dependent variables chi square

Is it possible to run chi square on independent and dependent variables that are both dichotomous (e.g. "0-No" and "1- Yes")?
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2answers
51 views

t Test, Chi Squared or logistic regression..?

20 subjects Day 1. Shooting test - Basketball free throw shooting accuracy (number of successful shots out of 10) Day 2. Given coaching and can practice technique. Day 3. Shooting test again (as ...
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vote
1answer
28 views

Why does my power vary markedly between a z-test (2 proportions) and a chi-squared test?

I have two groups, with 100 people in one group(1) and 80 people in the other group(2). 42% of group 1 love cake. I am wondering what proportion of the 80 group 2 members would need to love cake for ...
0
votes
2answers
22 views

Chi-squared for multiple samples

I have a set of data from an experiment where people are asked to remember items of different types; let's call them A, B and C, such that they can either recall them or not. Here is an example ...