# Tagged Questions

Refers to a measure of association between two binary variables. If $X,Y$ are binary outcomes and $p_{ij} = P(X=i,Y=j)$, the odds ratio is equal to $${\rm OR} = \frac{ p_{11} p_{00} }{ p_{10} p_{01} }$$ When ${\rm OR} 1$ indicates a positive relationship. More info is available at ...

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### Interpreting odds ratios less than 1 with 3-category outcome

I have a 3-category ordered outcome (food consumption: 1=no food, 2=less food, 3=more food) and a 3-category ordered predictor (food exposure: 3=no time, 2= less time, 1= more time- whereby 3=no time ...
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### Ordering ratios

We have an experiment where we observe a random number of objects (samples) and we measure how many of those are defective. Imagine that this is done in different factories that they produce these ...
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### Estimating the effects of cumulative odds ratios - additive or exponential?

I have run some regression models that examine the effect of variable X (a 15 point continuous scale) on Y (a binary variable - not perform/perform a particular behaviour) using logistic regression. ...
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### Concerns about the size of odds-ratio estimates in binary logistic regression model

I am creating some binary regressions and am wondering if I should be surprised by the size of the odds ratios. In this particular example, the dependent variable indicates whether a student can ...
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### Odds ratio with zero cell counts

I am trying to run a binomial GLM but have some zero cell counts resulting in estimates of +/- infinity. In the text book "An Introduction to Categorical Data Analysis" Agresti A. (1996) it suggests ...
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### PROC LOGISTIC, GENMOD

How can I get the standard error for odds ratios. I know how to obtain ORs, either by exp the estimate or by using LSMEANS or SLICE statements. Unfortunately wasnt able to find the options to have ...
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### Calculate z-score from odds-ratio

I want to calculate the z-score for a distribution for which I know the odds-ratio, and the p-value. I also know the upper and lower 95% confidence limits for the odds-ratio. An example with two-data ...
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### Measures of effect size for chi-squared tests

What are the different measures of effect size used for chi-squared tests / binomial data? I'm already at least somewhat familiar with the phi coefficient and odds ratio. I've heard of Cramer's V and ...
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### Converting odds ratios to Cohen's d for meta analysis

I'm conducting a meta-analysis largely on mean differences data, however I have several articles that report only an odds ratio, N, p value, and confidence interval, and I need to convert this ...
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### Calculate odds ratio confidence intervals from plink output?

I have output from plink haplotype analysis, however I do not have the raw data. Here, is the output for Haplotype-based association tests with GLMs: ...
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### How to estimate Relative Risks in Multivariate Binary Logistic Regression Models, instead of Odds Ratios?

All software programs I have tried report only odds ratios (ORs) for binary logistic regression predictors (as exponential of the betas). I am interested to know how can I compute the relative risk ...
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### Odds and odds ratios in logistic regression

I am having difficulties understanding one logistic regression explanation. The logistic regression is between temperature and fish which die or do not die. The slope of a logistic regression is ...
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### Calculate allele-specific odds ratio

I'm new at genetics and I'm currently learning how to compute allelic odds ratio for an association analysis. I'm using online programs in which one enters the allelic counts for the case and the ...
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### The bootstrapped confidence intervals for ORs are strangely big or small in my binary logistic regression. Are they valid in the first place?

This question is an extension to my previous question, although it is not repeated. My bootstrapped ORs are OK. They are equal to non-bootstrapped ORs. However, the confidence intervals of the ...
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### Standard Deviation of percentages

Say I have a bunch of weighted coins that should show heads 90% of the time. I take a bunch of them, throw them in a box, and calculate the percentage of coins that landed on heads. I do this a bunch ...
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### Calculate log2 ratio

I have to calculate log2 ratio for odds and don't know how to do it. Group A Group B 0.031571 0.0170071 There are occurrences of event in ...
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### Interaction Test with Odds Ratio

Reading Pocock et. al on subgroup analysis, the authors describe calculating an interaction test given 2 odds ratios (and the count data used to get them). Specifically, ...
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### Should I convert bootstrapped confidence intervals for logistic regression coefficients (betas) to CIs for odds ratios (ORs)?

I have bootstrapped my multiple logistic regression model. SPSS does report OR and its confidence intervals for a non-bootstrapped multiple regression, but when it bootstraps the same model, it just ...
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### Extremely high Odds Ratio, but no multicollinearity

Within my multi-level analysis, I have a dichotomous dependent variable 'tol' where '1' is tolerant and '0' is not tolerant. Next to that, I have a nominal independent variable which included an ...
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### Exact version of Bowker's test?

I know there is an exact version of McNemar's test for symmetry, and am just wondering if there is an exact version for Bowker's test. From my understanding the exact version of McNemar's test uses ...
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### Regression with a ordinal scale dependent variable in the context of panel data

In my panel data I observe a quite large amount of different individuals for a fixed time duration. The time axis is fixed for every individual, i.e., I observe 20 time points for every individual. ...
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### Different odds ratios from formula and R's fisher.test

In the following example ...
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### Why is the CI for an odds ratio not always centered on the sample value?

Also, what will tend to produce a CI in which the sample value is far above the center, or far below the center?
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### How to compare whether the odds of success of different levels of a predictor are different from 0

I hope I am able to word my question clearly. Suppose I have a model below: glmer(Y~X + (1|subject), family="binomial", data=dat) The intercept is the log odds ...
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### Logistic regression and odds ratio

If the odds ratio is greater than one with an insignificant p value for a variable in logistic regression should the variable be kept in the model? Can I select the variable with odds close to 1? ...