Questions tagged [contingency-tables]
Tables of counts (occasionally proportions of marginal counts), arranged by (at least) two marginal categories, displaying bivariate or multivariate frequencies. Sometimes called crosstabs.
566
questions
0
votes
1
answer
23
views
Statistical test for 3x2 contingency table, with cases:controls matched 1:5 (i.e. non-independent)
I am examining a cohort of cases against controls, matched at a 1:5 ratio (on sex, birth year, and residency/postal code at time of diagnosis).
Education level
Cases (n=206)
Controls (n=957)
p-value
...
- 21
0
votes
0
answers
7
views
Two-sample statistical significance test taking into account group membership (proportions) and numeric comparison
Say I have two samples of observations, S1 and S2, which can be of unequal sizes. For each observation, I have two variables: G (a categorical group assignment, say it is binary with values A/B), and ...
- 161
0
votes
0
answers
40
views
Chi-squared test with more than two variables, or should I run a different test?
I am looking at whether certain animals or categories of animals are more likely to use human-made trails than natural trails. We used camera traps and recorded for every case which animal it was, ...
8
votes
2
answers
425
views
Infinite upper confidence interval using Fisher exact test in R
I am having trouble interpreting the upper confidence interval for the odds ratio (OR) after executing Fisher's exact test in R.
I have the following contingency table which contains the response ...
- 81
2
votes
1
answer
65
views
Standardised residuals in contingency tables and statistically significant result
I have the following contingency table that results in statistically significant result of Pearson's $\chi^2$ Test for Count Data.
I've computed Pearson residuals that should have the same properties ...
- 135
0
votes
0
answers
8
views
Enrichment of positive cases within paired data
I have analyzed 47 cancer samples from tissue and blood. in the tissue 40 are positive for a virus and in the blood 8 are positive for the virus Importantly, these 8 are the same patients that are ...
- 211
2
votes
1
answer
71
views
Compare two contingency tables with the same structure
I want to compare two contingency tables A and B with the same structure (same columns and rows). My first idea was to use chi squared distance $\sum_{i=1}^{p}{\frac{(O_i-E_i)^2}{E_i}}$. But, some ...
2
votes
2
answers
63
views
Comparing two association matrices (contingency tables)
I am looking for a significance test to compare between two association matrices (contingency tables) - preferably to test whether the odds ratio is the same. I have looked at some questions here but ...
- 101
2
votes
2
answers
52
views
Bayesian inference based on a 3$\times$3 contingency table
How do I make inferences about population parameters based on a 3$\times$3 table of observations? In "Bernoulli's Fallacy", Aubrey Clayton provides this (Table 5.8).
Democrat
Republican
...
- 326
0
votes
0
answers
22
views
How can I update a contingency table based on evidence?
I have a series of contingency tables that are my population benchmarks and survey data. Practically speaking, we know the population benchmarks are largely, but not entirely, accurate; there are some ...
- 107
1
vote
1
answer
50
views
How to calculate the p-value of a log-odds ratio, given that the variance depends on the observed frequencies?
I am a bit confused about how people calculate p-value when calculating odds-ratios.
The log-odds ratio (LOR) for a contingency table with two entries is $L = \log \frac{p_{1}}{p_{0}}$ and has an ...
- 130
0
votes
0
answers
15
views
Anova with response dependent on other variables that arent the predictor
I am running into difficulty determining the best way to analyze my data. So, as backgroud I have a dataset containing the variables MONTH, REGION, COUNT, and YEARS. MONTH, REGION, and YEAR and all ...
- 11
1
vote
1
answer
82
views
Test to compare multiple contingency tables
I have three contingency tables with the variables month and region that contain the frequency of the sighting of a particular bird. Additionally, the tables differ only by counting frequencies from ...
- 11
0
votes
1
answer
94
views
Does Cochrane-Armitage test require an obvious trend in contingency table?
I'm trying to determine whether it's appropriate to use the Cochrane-Armitage trend test on this set of data? I don't have any specific hypotheses I need to investigate, just to choose an appropriate ...
- 13
1
vote
0
answers
53
views
Inference for Contingency tables [closed]
Assume two paired binary vectors, $v^A,v^B$. We can easily construct a contingency table looking like:
$v^A_i=1$
$v^A_i=0$
Totals
$v^B_i=1$
$a$
$b$
$a+b$
$v^B_i=0$
$c$
$d$
$c+d$
Totals
$a+c$
$b+d$
...
- 3,028
0
votes
1
answer
85
views
margins=True option in pd.crosstab influences the outcome of chi2_contingency test. Why?
I understand what the margins=True option in pd.crosstab does, but I don't understand why it would influence the outcome of the chi2_contingency.
Here an example:
...
- 23
0
votes
0
answers
40
views
Relative Risk and Odd ratio for N x N x N table
I am trying to calculate RR for case where I have N x N x N table. First N is City (20 cities) second N is Age group (5 groups) and third one is Industry (4 ...
- 1
3
votes
1
answer
49
views
I have an issue summarising highly skewed data in a table
I have a numerical ordinal dataset (eg. 1-10) that's very highly skewed, with >90% of the values at 10. How can I best summarise this in a table? The median/IQR gives '10 (10, 10)' (which doesn't ...
- 31
0
votes
0
answers
25
views
Are marginal probabilities a mixture model of the conditional probabilities?
In a contingency table, is it correct to say that the marginal probabilities are a mixture model of the conditional probabilities?
Also, is it correct to say that these marginal and conditinal ...
- 11
2
votes
0
answers
240
views
The asymptotic distribution of a Pearson Chi-Square test statistic (test for independence)
There are many different Pearson Chi-Square tests. The test statistics are always a sum of scaled and squared deviations. Some are written as a single sum, and some are written as a double sum (the ...
- 19.8k
2
votes
1
answer
91
views
Making sense of a reviewer's "30 observed counts minimum per cell" requirement on a contingency table
I'm perplexed by the comment of a reviewer, who has taken issue with the sample size from a study I conducted. He says, relatively to the 2X2 contingency table below and a (significant) 2-sample test ...
- 2,386
1
vote
1
answer
79
views
What will happen to my results if I use Fisher's exact test with unfixed marginal totals?
I've been trying to get my head around the controversy that surrounds Fisher's exact test.
I often use the test in the something like the following way:
A survey asks respondents two questions: "...
- 133
3
votes
0
answers
158
views
Alternatives to logistic regression if there are zero counts
I have three variables (let's call them $A$, class (both binary) and age (numerical)), and I want to test if there is a difference in the presence of A between the two classes, with age as a potential ...
- 368
0
votes
0
answers
26
views
Statistical test for odds ratio when 1. N is large and not meaningful; 2. replicates are present
I'm investigating the co-occurrence of 2 types of events (var1 and var2). The hypothesis is that ...
0
votes
0
answers
18
views
Replicated experiment with categorical response and predictor
A set of experiments is performed under n conditions, with each experiment resulting in a series of events classified in k categories (k<10). Each condition is independently repeated m times.
...
- 101
0
votes
0
answers
30
views
No theoretical frequency should be less than 5 [duplicate]
Why does the theoretical frequency in chi-square distribution should not be less than 5? What's the concept behind pooling the preceding and succeeding frequency to make pooled frequency more than 5?
- 1
0
votes
1
answer
51
views
Calculate correlation of nominal and ordinal variables and hypothesis test in r
I would like to statistically analyze three variables.
One variable is "consortium mostly academic" (nominal, dichotomous), the second variable is "evaluation method" (nominal, non-...
Mec-Eng
0
votes
0
answers
33
views
How to apply Bayes' theorem on a contingency in which the sampled distribution differs drastically from the entire population?
Summary: How can I calculate my probability of being truly positive based on a contingency table that has a completely different distribution than the total population?
I was recently confronted with ...
- 1
1
vote
1
answer
193
views
Chi-square test for two vectors with very identical values
I have two vectors with two levels:
vector 1:...
- 21
1
vote
1
answer
97
views
Contingency analysis of a 3x3 table via Chi2, log-linear and Poisson GLM - how to interpret this result?
I have a dataset describing age of wine in 3 classes of quality.
...
- 21
0
votes
1
answer
100
views
Chi-squared test for equality of proportions
This question is question 12 from Problems 10.3 from Rohatgi's An Introduction to Probability and Statistics.
Of 25 income tax returns audited in a small town, 10 were from low and middle income ...
- 113
0
votes
0
answers
187
views
Non-numeric argument to binary operator
I'm trying to find out a model that adequately describes effects of gender and length on food choice. For gender; 0=Male and 1=Female, length; 0=Subadult 1=Adult, Choice; F=Fish I=Invertebrates and O=...
- 3
0
votes
1
answer
98
views
Covariance of cells in random contingency tables
Say we have $n=3$ bins and $m=3$ different coloured balls (30 red 20 green and 50 blue) in an urn. We draw randomly without replacement a ball from from the urn and place it into the bins. The first ...
- 68.3k
0
votes
0
answers
22
views
To analyze some percentage structure, is Breslow-Day any different than Chi2 for contengency table?
I was asked to compare three groups for their percentage structure. Let me explain - there is a categorical variable X with 3 levels: <100, 100-200, > 200 units. That's all I have and I have no ...
0
votes
0
answers
90
views
Should a contingency table be "symmetric"?
Im am running a fishers exact test on some data but im unsure of how the input contingency table should be formatted.
Option 1
...
- 1
1
vote
0
answers
30
views
Perform goodness-of-fit test on multiple contingency tables
I want to test my theory against a set of scenes. Specifically, I have 10 2x2 contingency table with observation and expected frequencies. Since there is only one model rather than 10 different models,...
- 11
1
vote
0
answers
36
views
Caveats in analyzing 2x2 contingency tables
after reading this paper https://onlinelibrary.wiley.com/doi/10.1111/1440-1681.12052 I have real troubles deciding which test is most suitable for my analysis.
The data is following: a group of ...
- 111
0
votes
0
answers
34
views
Collapsibility Conditions for Multiway Tables
Why is the WX conditional association the same as the WX marginal association in log linear model (WX, XYZ) (four-way table) and not in the log linear model (WX, WZ, XY, YZ)?
I saw on the internet to ...
- 3
1
vote
0
answers
58
views
Testing Relationships surrounding Social Media Engagement
I'm sure I have a very easy question I'm trying to answer, but as a qualitative researcher who has found themselves trying to help an undergraduate on a quantitative project, I need some help. I'm ...
- 11
2
votes
1
answer
464
views
Chi-Square Test for multiple-response variables?
I have two categorical variables but one of them has multiple responses. After searching online, I came to find the Rao-Scott Chi-Square Test for such data, but little was found about some useful R or ...
- 21
0
votes
1
answer
11
views
Different sub-population sizes in grading data
I am relatively new to statistical analysis.
Let's say I have a data set of 5000 report card grades
3000 (60%) are "A" grades
100 (2%) are "D" grades and
25 (0.5%) are "F&...
0
votes
0
answers
26
views
Does Fisher exact test impose restriction on sampling design? [duplicate]
It is known that Fisher exact test assumes that all 4 margins of 2 by 2 table are fixed. $\chi^2$ test does not impose restriction on sampling design beforehand in general where I mean $\chi^2\sim\sum ...
- 1,365
1
vote
1
answer
109
views
How to generate data or sample data from a summary tables?
I have a dataset like this:
I only have summary tables of the "loneliness score" for overall, for each sex, each age group, and sex * age interactions. Besides this, I have 23 items that ...
- 21
1
vote
1
answer
45
views
Determine if a categorical variable occurs at a frequency greater than chance with a boolean outcome
I am looking for the proper statistic to answer whether which categorical items (from a long list) occur at frequency greater than chance with each state of a boolean variable.
More specifically, I ...
- 11
1
vote
1
answer
369
views
0
votes
1
answer
171
views
What is the $\chi^2$ contingency test really showing?
I have a friend who used this function to compute a chi-squared contingency table in a paper they are writing, and I don't think I fully understand what the results of this test are.
Function ...
- 139
0
votes
0
answers
18
views
How to infer unknown cell frequencies (effect of a variable) if table marginals are known and cell frequencies for another population is known?
I want to infer cell frequencies (or conditional probabilities) for a population table where:
I know the marginal totals but not the cell frequencies, and
I know the cell frequencies for a table of a ...
- 107
0
votes
1
answer
30
views
Quantifying Dependency in Chi Squared Test
I am running a Chi Squared test on nominal values and this is the contingency table.
...
0
votes
1
answer
71
views
Correlation betwen lines and columns in a non-mutually exclusive contingency table
I am interested in testing whether there is a correlation between a line and one or several rows in a contingency table.
Let's imagine this dummy dataset:
In rows, I have the types of meal that you ...
2
votes
1
answer
149
views
Iterative proportional fitting with constraints
I am trying to determine if it is possible to conduct iterative proportional fitting with some constraints. To give a dummy example of my goal:
Say I had data for two towns, A and B, on the ice cream ...
- 45