Questions tagged [odds]

The odds of an event is the ratio of the probability that the event will happen (p) to the probability that it will not happen (1-p).

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What are the odds [duplicate]

What are the odds Ive met my other half? Thing is I already know I have with this undeniable experience we had when our souls actually collided together as we were one. I just want to know what ...
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What probability or weight should I assign to X so that it has a Y% chance of being one of the 6 items selected out of a population of 12?

I have a population of 12 items, let's call them A through L. I'm going to be drawing 6 of those items out of the population without replacement. So you can't choose the same item twice. What I know ...
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What is the difference between standardized mortality ratio (SMR) and odds ratio (OR) from age matched case and controls?

My question refers specifically to comparisons of chronic diseases, say heart failure (HF), between a specific group of interest (eg, diabetics) and a reference group (non-diabetics). SMR is the ...
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Generate odds ratios across deciles / quantiles of an indpendent variable

With reference to the following figure from Bellomo et al., 2011: How exactly are the odds ratios across the deciles 'referenced against the 4th decile' calculated? My initial impression is that a ...
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Multiple non-independent tests, how to determine post-test odds

Let's say a patient receives two biomarker tests to help with diagnosis of a disease. Each test measures a different mechanism of the disease, but these two mechanisms are not independent, so the ...
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Betting odds with team win and draw

So a game can have 3 outcomes: Team 1 wins: 36% chance. Payout is 2.15 Team 2 wins: 34% chance. Payout is 2.45 Game is a draw: 30% chance. Payout is 2.66 How should I be thinking about making one or ...
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When Can I say odds ratio is important to analyze my data

Lets say in my data if I generate odds ratio between 2 variable A and B and get that the odds ratio is 2-5 is that a good thing to dive deep further or should I move to other relations .
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What are the selection odds

If 30 ice-cream sticks are numbered 1-30 and placed in a bowl, what are the odds that when picking two at a time, and then returning them to the bowl, any random pair will never be picked?
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Correct interpretation of odds ratio

I am wondering what the correct way of interpreting an odds ratio is. For example, suppose we have that the probability of success is $p=0.8$. Then, the odds ratio is: $$ \frac{p}{1-p} = \frac{0.8}{0....
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What are the % Odds?

NEED SOMEONE GOOD IN MATH! My father, my brother & myself all have AB- Blood Type. According to The Stanford School of Medicine Blood Center around 0.6% of the population has the ABneg blood type....
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Probability of picking winner of Survivor

I'm hoping for some help with determining a formula. My friends and I are watching the Australian Survivor show where 24 players are left on an island and a player is eliminated each episode until ...
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logistic regression log odds to probability issue in R

I have the following issue in R. I perform logistic regression in R: logitMod <- glm(dependent_var ~ var1, var2, varN, data=traindata, family=binomial()) ...
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Predicting elections: Probability distribution from betting odds and dependence

Suppose I want to find the percentage of votes each party will get in elections. I have following odds from betting companies. My first thought is to find the probability for each party achieving a ...
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Regarding interpretation of Odds Ratio

I have just read in my professor's lecture notes that the Odds ratio $\psi(x)$ takes non-negative values, and that the the effect of $X$ (the predictor) on $Y$ (the binary target variable) is measured ...
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Interpreting large logistic regression coefficients

I've run a logistic regression and have one continuous variable with a log-odds coefficient of 4.144. From what I understand about converting to odds, this would have an exp(4.144) = 63.05 increase ...
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Interpretation of two odds ratios derived from two different cohen's ds, comparability for meta-analysis?

I have a question regarding the conversion of cohen's d into odds ratio (OR) and the comparability of results from two different situations. I wonder if the ORs derived from the two situations can ...
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Logistic Regression, Advantage of GLM's : “*If the link produces additive effects, then we do not need constant variance*”

From this page: The bottom section : Summary of advantages of GLMs over traditional (OLS) regression contains the advantage If the link produces additive effects, then we do not need constant ...
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Comparing adjusted odds ratios in a model

I have a pretty basic question. Say I run a logistic regression model with 2 variables both dichotomous. falls= sex+stroke+depression. I get 3 different odds ratios, one for males vs females, one for ...
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Why am I expected to take n/m attempts to complete something with m/n odds?

I assume there are various ways of explaining it, but what's the most intuitive (yes I understand that is a relative concept) Edit due to request: Obvious example: There is a 1/6 chance of rolling a ...
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How to calculate the odds of a highly improbable event?

I'd like to calculate the odds of a chess player A to gain 1000 Elo points in a year. Elo rating is an indicator of a player's strength at a given moment (wikipedia - elo). a) It doesn't matter what ...
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What is the interest to implement a statistics model in a groupby object instead of use the whole groups in a sample?

I saw this topic and also this one in dask documentation. I wonder what is the real interest to make a model for each group instead of considering a whole sample where all groups would appear? As far ...
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How to calculate CI for Odds ratio, Given Cohens d and ci for Cohens d( data is given as mean)

I have means(x) and Std deviations of 2(intervention and control) groups. I wanted to find Odds ratio with CI. I calculated the cohends d and CI first using,https://campbellcollaboration.org/escalc/...
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How to create a logistic regression model based on a two way table

question Given a table such as : $$ \begin{array}{ll|ll} & A & {} \\ & & 0 & 1 \\ \hline B& 1 & 44 & 27 \\ &0 & 443 & 95 \end{array} $$ If I ...
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If I have the implied probability of something how do I convert that into decimal odds? [closed]

I'm really struggling to find examples of converting implied probability back into European decimal odds. Say I have the implied probability of a horse to win at 66% of the book (no overrounds for ...
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Computation and Interpretation of Odds Ratio with continuous variables with interaction, in a binary logistic regression model

Question A binary logistic regression model has been fitted, with the following output; ...
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SPSS - Binary logistic regression: classification cutoff

Let's say I want to evaluate the predictive value of a continuous variable in the prediction of malignancy (event/status) of a tumour. Malignant = 1 Nonmalignant = 0 In SPSS, I can run a binary ...
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Difference in logits to difference in probabilities

a) Is there any way to prove that you cannot compute a probability difference when you know a logit difference? b)In general, is there some acceptable way to convert distances in logodds space to ...
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Betting with odds

I have a game where I can bet on two teams: One team has odds $1.7$ The other has $1.5$ I understood that the one that pays off $1.5$ has an higher probability of victory, so it pays less. But how ...
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Odd Number Probability

How do I calculate the probability of randomly picking a number in the range from 0 to 10000 where exactly two of the digits is odd. For ex 5001 or 1010 etc.. and how would I do the same calculation ...
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3 D6 pick 2 vs 2 D6 with 1 reroll

I was wondering if there is any statistical difference between rolling three 6 sided dice and taking the best two (looking for a 7 or higher) and rolling two 6 sided dice with the option to re-roll ...
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Is there a possibility to calculate the odds of the following scenario?

The following is a true situation that I faced and I was wondering if it is possible to roughly estimate the odds of it happening (like you sometime see rough estimations of "The odds of you winning ...
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Logistic regression with independent variable values less than 1

I have one independent variable which has values less than 1, and want to see how the odds of having a disease change when the independent variable increase by 0.1. I ran a binary logistic regression ...
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Crude odds ratio

I came across following definition of crude odds ratio in binary logistic regression: Crude odds ratio is when you have only one independent variable And also I heard: Crude odds ratio is when ...
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How are these odds created?

I've always been a bit baffled by how Vegas creates sports odds. Not so much the process of how did the oddsmakers decide that Option A has odds of X/Y (that obviously is fairly subjective and not ...
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Unbiased estimators of the log odds

In the book of Lehmann and Casella (2003) page 83, a random variable $X$ is distributed according to the binomial distribution $Bin(n,p)$, $n$ the number of trials and $p$ the success probability. ...
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Odds Ratio and gene mutations association

I have a simple (yet to me still trivial) problem to submit to you. I have a dataset of a group of patients affected by a disease, for which the presence of several genes mutations was inferred. Each ...
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What is a simple intuitive definition of Odd? [duplicate]

From what i read "The probability that an event will occur is the fraction of times you expect to see that event in many trials. The odds are defined as the probability that the event will occur ...
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The difference between the logits of two probabilities is the logarithm of the odds ratio? Correct/Incorrect?

I was reading a Wikipedia article on the logit function, and I came across the following in the definition section: If $p$ is a probability, then $p/(1 - p)$ is the corresponding odds; the logit of ...
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model building including very large or very small OR

I am using logistic regression for a binary outcome. When building a multivariate model, is including insignificant univariate variables with OR >0.5 and <1.5 appropriate? And why?
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What are the odds of both my Grandmothers passing away on the same 24 hour day? [duplicate]

Yesterday (April 7th, 2018), my Grandmother from my Mom's side passed away. Later on that same day, less than 24 hours apart, my other Grandmother (Dad's Mom), passed away. My question is simple; what ...
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Interpreting odds ratio of multiple comparisons from a logistic regression model (using R)

I recently ran a logistic regression on categorical data and ran a Tukey multiple comparisons post hoc analysis using the glht ...
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95% confidence interval for log odds

I'm looking at data from the O-Ring Challenger disaster and wasn't sure how to get a 95% confidence interval for a particular estimated log odds. In this case, I'm considering a logistic regression ...
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How to average “Odds likelyhood” when probabilities from multiple models are involved?

I am trying to understand a problem confusion. Say, we have two models (m1 and m2) that predicts probability of "rain" on a particular day. If I am trying to calculate average odds of rain, which ...
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There are 100 people in a room. What are the odds that the shortest person in the room is born in February?

This is a follow up question to the previous "There are 100 people in a room. What are the odds at least 1 person is born in January?"
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Correct way to interpret odds ratio

I'm looking at a table of logistic regression results. Specifically, the table shows "Logistic regression model of hypertension status in relation to lead biomarkers in the normative aging study, ...
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Optimal wager strategy for high win chance / high odds game

In a rigged game of chance where statistically I am expected to win, is there a difference in terms of expected profits, risk, etc - between betting the same amount of money each time (for example ...
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Logistic regression to test difference between two groups with multiple levels

I have a dataset (see example below) with 1200 rows and 3 columns: dependent_var (yes and no), group_var (1 and 2) and var1 (1, 2, 3 and 4), where var1 belongs to either group 1 or 2. The two groups ...
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Reporting a Negative Logit/Log Odds as an Odds Ratio for a Continuous Predictor in Logistic Regression

In the social sciences, people typically report and interpret an odds ratio (OR) < 1 for a binary predictor which has a negative association with a binary outcome. But the social sciences, of ...
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How exactly do the odds multiply when “evidence” adds up?

I was reading an answer explaining the justification for using the simoig function in logistic regression. The reason given was essentially "when evidence adds up, the odds multiply". This is the ...
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Odds ratio for poisson regression

Can I compute Odds ratio coefficients and their 95% CI from a Poisson regression (GLM) using the exp function? I have an ordinal dependent variable (i.e., a GS of a scale) and some independent ...