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

learn more… | top users | synonyms (1)

1
vote
1answer
49 views

$t$ test vs $\chi^{2}$ once sample is split into two groups?

I would appreciate some guidance regarding the use of a t test vs $\chi^{2}$. I am looking at some small set of demographic data (n only 13). I have divided up the sample into two sets, those with ...
0
votes
0answers
16 views

Designing bootstrap test for sparse data sets comparison

I have two categorical data sets which I would like to 'compare', that is, test whether they are drawn from the same population. Data sets are pretty large (up to 3 million entries), but appear to be ...
1
vote
0answers
22 views

Best proportions test based on counts (accuracy, distribution, etc)

I'm trying to compare two sets of counts over totals. For example, subject 1A will have 40 out of 600, and subject 1B will have 3 out of 20. How do I compare these proportions and counts while taking ...
1
vote
1answer
23 views

What does y argument do in chisq.test in R?

The chisq.test function in R includes a y = argument, which is to NULL by default. The help ...
2
votes
1answer
20 views

Is there a significantly different number of people between groups?

How do I estimate whether a given number of people across groups (say, 72 people in group 1, 95 in group 2 and 70 in group 3) significantly differs from a random distribution of people across groups? ...
1
vote
1answer
22 views

Appropriate Statistical Test for multiple groups

I have a question regarding which test I should run on some data. I have small groups of people who answered questions. The answers to these questions have been classified as correct or incorrect. ...
1
vote
1answer
55 views

Comparing large categorical data sets with low or zero counts

I'm dealing with a biological feature which can be classified into $2^{20}$ categories. I also have two pretty large data sets of 1 and 3 million entries. Actually, only around 30 thousand categories ...
2
votes
0answers
17 views

How to approximate error on Chi-Squared Fit when bin counts are zero

I am using a galaxy image simulator that provides a 2D histogram that has the number of photons per pixel (bin) $N$. I am currently using a least-squares residual: $\sum_{bin}(f_{data}-f_{model})^2$ ...
0
votes
4answers
34 views

Two groups are significantly different? Test to use

I have two groups of discrete data (integers): ...
0
votes
1answer
24 views

prop.test: correcting for large number of observations

This is not really a coding question but more of a statistical question. I'm doing a proportions test on multiple proportions for many subjects. For example, subject 1 will have multiple proportions ...
1
vote
0answers
33 views

Different p-values between Wald Z and Wald Chisquare

I have used lme4 for mixed effects models of reaction times and accuracy rates. I could not use lmerTest because the type of model I was using are not yet implemented there (problem with predictors ...
1
vote
0answers
23 views

Overly-sensitive goodness of fit measure: where did I go wrong?

I'm using the chi-squared goodness-of-fit measure to evaluate instances of a fairly complicated model, but the evaluation is unbelievably sensitive to small variations in the model parameter values. ...
4
votes
1answer
99 views

chi square test or Z test?

SO I have an outcome from a biological experiment, where I have counted the number of dead cells upon a mutation. For example, in once case - out of 120 cells we saw 16% of the dead cells, but our ...
2
votes
1answer
62 views

Proper analyses for 2x2 contingency tables

So I have multiple questions about the different types of analyses that can be used on a 2x2 contingency table and when different analyses should be used. To open, I'll note that this stems from my ...
8
votes
2answers
95 views

Combining $\chi^{2}$ tests

I have a problem with statistics. I'm looking at whether variation in the concentration of a certain substance affects how strongly insects are drawn towards it. I did this by baiting insect traps ...
2
votes
1answer
18 views

Multiple value Chi Squared test in SPSS

I am currently doing a study into factors that affect mortality in a particular type of bacterial infection. I would like to compare certain patient characteristics. One of which is the specialty ...
0
votes
0answers
36 views

Chi-square test for one group

I'm struggling with this problem. For the analysis of my test, I was instructed to use chi-square test for one group. I use Statistica and everywhere I try to do this I need the expected values​​, ...
1
vote
0answers
14 views

Chi-squared test where observations can have multiple categories

I am investigating patterns in click-order on images. A user is asked to click on an image in 5 places (can be the same place). This sequence of 5 clicks makes up a graphical password. I am looking ...
1
vote
1answer
48 views

Why use chi-square (or other) statistic over regression modeling for 2x2 contingency tables?

I have a question regarding the use of logistic/log-linear regression vs. contingency test statistics, such as chi-square. Can someone explain to me why it would ever be preferable to use test ...
0
votes
2answers
71 views

Best way to test for co-occurrence of measures

I have some data with temporal measures over time. I'd like to test whether two binary variables co-occur more often than chance would predict, and I'm wondering the best (simple) way to do that. The ...
0
votes
0answers
19 views

Measure of probability of obtaining a certain $\chi^2$ given the number of trials

I am calculating an equation with several random components a large number of times, and in order to select my final answer I choose that with the minimum value for $\chi^2$. I am hoping to find some ...
0
votes
0answers
10 views

How to interpret merits in Weka with ChiSquaredAttributeEval and SVMAttributeEval?

I want to interpret the goodness of attributes using feature selection with 10-fold cross validation. With ChiSquared I get something like this (deletet attributes with merrit was 0 in all folds): ...
1
vote
0answers
5 views

Probability of certain value of $\chi^2$ given a number of trials

I am calculating a result and an associated $\chi^2$ via an iterative process that makes use of 3 random numbers (randomly sampling a Gaussian) in an equation, and I select as my final result the one ...
4
votes
3answers
59 views

Understanding $\chi^{2}$ and Cramér's $V$ results

I have two groups of buyers, A and B, and I want to test whether the difference between the percentage of them who would buy a ...
0
votes
0answers
20 views

Sampling weight, logistic regression and chi-square analysis [duplicate]

I have some questions. I am doing logistic regression. but my sample is small(n=129). And in DV, the smallest number of cases is 27(1'). Actually, I hope to use 12 predictors. However, I know the rule ...
0
votes
0answers
10 views

Which feature selection method to use for classification problem

I have to do some feature selection for a classification problem with numeric features. I am not sure which feature selection method to use. Chisquared test or Spearmann's rank correlation ...
0
votes
0answers
11 views

Independent Categories with multiple responses, chi-square too simple, MRCV log-linear model too complex?

Hello all and thanks in advance for your consideration, My research question is simple: Do lynx have a different diet in summer compared to winter? Data structure looks simple at first glance, ...
0
votes
0answers
10 views

$\chi^2$ goodness of fit - how to compute expected counts when $\exists$ unknown parameters [duplicate]

This isn't my original problem, but I'm posting a simplified version and then I'll try to see if I can apply it myself to my original problem. (yay for self-learning) Suppose I have a sample and I ...
5
votes
1answer
229 views

Is the beta distribution really better than the normal distribution for testing the difference of two proportions?

I'm working at an online agency, where we run a lot of AB testing in order to test differences in proportion between two groups (test vs. control). Standard practice in the industry for testing ...
0
votes
0answers
21 views

How to corretly scale sum of squared residuals of two different sets of data in order to compare them?

I did numerical simulations of two different systems that returned me N=1000 histograms expressed as $\{x,y,y'\}$, where $x$ is the independent variable, $y=P(x)$ is the probability distribution ...
0
votes
1answer
32 views

How can I do a chi-square test without being given the critical value table?

I have a random number generator that generate integers within [0, r). I want to write a piece of code to test whether the numbers from it are truly uniformly ...
0
votes
0answers
40 views

Combining chi-squared statistics

I have performed a survey in which users click on an image and the position of this click is recorded. I want to see if where a user clicks is independent of an attribute of the user (say gender). ...
1
vote
2answers
37 views

Multiple comparison on subgroups and overall comparison

I am trying to work out is there is any association between occurrence or not of an event in around 500 individuals and their randomised binary grouping (intervention vs placebo). However I also want ...
1
vote
2answers
49 views

Can Fisher's exact test accept a 'vector of probabilities'?

The R function chisq.test allows a 'vector of probabilities' to be set with the p argument. Is there an equivalent for ...
0
votes
0answers
18 views

Is it possible to take into account a variable that isn't really specified?

When you run a statistic test, is it possible to take into account a variable that isn't really specified? I'll give an example. We have to see if a certain word in a sentence is collective or ...
6
votes
1answer
58 views

Understanding the Chi-squared test and the Chi-squared distribution

I am trying to understand the logic behind chi-squared test. The Chi-squared test is $\chi ^2 = \sum \frac{(obs-exp)^2}{exp}$. $\chi ^2$ is then compared to a Chi-squared distribution to find out a ...
1
vote
1answer
32 views

Chi Square Analysis Percentages

I've used chi-square analysis in school, but was absent for the lesson, and I never quite got the hang of it. I've been successful with it in the past, but now I'm trying to use percentage values, and ...
1
vote
0answers
66 views

Is this normal to have big value of Chi Squared?

I am using chi squared for feature selection in text classification. However when I compute it I sometime have very big values. Like 100, 1000 or even 20000. Is this normal ? I wonder because I ...
2
votes
1answer
56 views

“Better” goodness-of-fit tests than chi squared for histogram modeling?

I work on data from a mass spectrometer that produces billions upon billions of count histograms, and I need a good way to test whether these histograms are consistent with one or several model ...
0
votes
0answers
17 views

Is it correct to compare two distributions of observed (that are means of observation) and expected values with chi square?

I have 2 classification methods that I want to compare. So I ran them on the same dataset and I obtained 2 different classifications. Then, I want to test if their classification is robust and how. ...
0
votes
0answers
31 views

Interpretation and understanding results from a chi square test for independence

I'm making a chi square test on data that has information about students. I want to find out whether there is a relationship between how well the students did on a particular test and the level of ...
1
vote
1answer
32 views

How to calculate degrees of freedom for chi squared test

I am very new to stats, and if the chi squared test is not the best way to handle this, please let me know. To simplify what I'm trying to do, I have many separate lists of genes. Each list is a ...
2
votes
0answers
33 views

Chi-squared test and binomial distribution

In some circumstances the Chi-square test can be replaced by a test based on the binomial distribution. The common issue with using the binomial distribution is that it may quickly become tricky to ...
1
vote
0answers
10 views

One-way Chi-Square goodness of fit and Cramér's V

Would it make sense to apply a measure of association test like Cramér's V on a 1xk table? I am a bit puzzled because in the literature phi and Cramér V are normally used on 2x2 or bigger ...
1
vote
0answers
22 views

Chi Square Test - Goodness of fit to test significance of incomplete system

A general question I'd like to ask. I have two systems, one has complete data, the other one we found only has 80% of data, the rest 20% is missing for reasons yet to be found. But for short term, I ...
1
vote
0answers
20 views

hypothesis testing in hierarchical trees

Suppose I have an hierarchical tree organising people according to their music preferences. Each person then has 3 extra properties A, B and C (e.g. parent's supportiveness on musical education). I ...
2
votes
0answers
30 views

What is the appropriate statistical test for Presence/Absence over time

I am assessing the presence or absence of a number of developmental milestones in mice in their first $21$ days of life. Each day, from the day they are born until they have $21$ days, I test if pups ...
2
votes
1answer
38 views

Which test to use to measure if target has been met?

The photo below is an example of the result i would like to obtain using the test which i cannot find in the article itself, i was hoping maybe any of you would know. I have tried to carry out chi ...
1
vote
1answer
35 views

Chi Square test to measure degree of association

I have a categorical variable with binary outcomes 0,1 (say Y), I want to study the association with other variables X1,X2,X3,X4,X5..... most of Xi's are categorical and few of them are continuous. I ...
1
vote
2answers
64 views

Multiple testing: contingency table or logistic regression approach for survey?

I have a survey asking a person's gender (M/F), geographic region (West, East, Midwest, South) and a few other demographic variables along with two dozen questions in which they can disagree / ...