# 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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23 views

### odds ratio for two variants of covid [duplicate]

I need to calculate the odds ratio for mechanical ventilation and death in relation to different early COVID-19 symptoms for two COVID variants - delta and omicron. How should I do it? I want to ...
49 views

### What is the intuition behind the odds scale?

What is an intuitive explanation of the odds scale? In a logistic regression such as $$logit(p) = \beta_0 + \beta_1 x$$ we often interpret $\beta_1$ by looking at the odds ratio, $e^{\beta_1}$, which ...
1 vote
49 views

### Interpretation of continuous variable in an odds ratio for logistic regression

I have an odds ratio of 1.02 for x variable (Age, a continuous variable measured in units "1 year"). My response variable is Y. I would interpret this as for every increase in Age by 1 year ...
1 vote
28 views

### Log of the odds in Logistic Regression

In simple logistic regression i noticed that many researcher neglect the constant part of the logistic regression equation. Log(odds) = a + b Gender (say that 0 = Female and 1 = Male) So the log of ...
26 views

### How to calculate Log odds contribution for different generated variables

In this paper, they are simulating data and calculating the log odds contributions for different kind of variables. The following is stated in the paper: Two multivariate normal predictors (A and B) ...
56 views

### Intuition of the log odds linearity assumption for logistic regression

I'm currently having trouble understanding the assumption of logistic regression that the input variables must be linearly related to the log odds. Specifically, what actually happens to the model ...
1 vote
180 views

### D&D Probability question: why am I wrong?

In Dungeons and Dragons, the primary die used for success or failure is the D20, or 20 sided die. A 1 is a critical failure, and a 20 is a critical success. When one has advantage, one rolls 2 dice ...
507 views

### Interpretation of Odds Ratio (OR) in Fisher's exact test

I've tried using R operating Fisher's exact test to test for independence of the 2 datasets below and struggling to interpret the Fisher report. Please have a look at the data and the Fisher's test ...
82 views

### Probability your name will be drawn out of a hat without replacement

Let's say you put your name in a hat with 7 other names (n=8). Only 4 names will be drawn from said hat. Each name will be drawn one at a time, without replacement. What is the probability that your ...
19 views

### Questions about the correct terms

I'm studying the Table 43A of the FBI's UCR database; I made my own Excel table to compare those numbers, now I am writing the explanations about each stats on a Microsoft Word document; unfortunately ...
1k views

### Flipping Coins : Probability of Sequences vs Probability of Individuals

Here is a problem I thought of: Suppose I am watching someone flip a fair coin. Each flip is completely independent from the previous flip. I watch this person flip 3 consecutive heads. I interrupt ...
58 views

### Question on Interpreting Results from rcspline.plot function

I have been using rcspline.plot() function to look at the preterm birth across interpregnancy intervals, the time between pregnancies measured in months, and I wanted to clarify the calculation of the ...
27 views

### GAMLSS BEINF Model s(x) coefficient log odds to odds interpretation. after logit link transformation

I am fitting a BEINF beta inflated model using gamlss in R. The response is a continuous variable and I have a single continuous predictor covariate with a default ...
40 views

### Chances of four people being drawn together

There are eight people in a golf group. There is going to be a draw to split them into two groups of four. There are four people within the group who would like to be drawn together. What are the odds ...
24 views

### What are the odds of 8 being drawn out of a group of 10 digits 5 times in 8 tries? [closed]

I am wanting to know the odds of something happening. What are the odds of 8 being drawn out of a group of 10 digits 5 times in 8 tries?
1 vote
55 views

### meanBEINF vs predict(model, type = "response') in BEINF GAMLSS. and determining odds of predictor variable coefficient

A variation of this question has been asked, but certain items remain unanswered - I am modeling the proportion of mortality (Prop) using a single continuous predictor variable which is temperature (...
1 vote
50 views

### How does Shapley obtain values in the probability space in tree classifiers?

By default, the Shapley values for a tree explainer (e.g. based on xgboost) are in the log odds space (where they are additive). However, there's a functionality in the package to obtain values in the ...
18 views

### Transforming linear mixed model effect estimate to odds of a predetermined increment of change

I'm studying patient reported outcome in relation to treatment modalities in cancer. To assess the effect of a specific treatment (yes/no) on a specific outcome (normalised to 0-100, repeated measures ...
404 views

### Probability of Dice and Coin flips

A friend and I were disagreeing about how you calculate the probability for the following. Seeing as both of us aren't that strong in stats I figured I would come here. Sorry if this question is a ...
40 views

### Have I found something new? (a formula for the odds of rolling at least one 1 when rolling an n-sided die n times)

The formula First, the formula I found for the odds of rolling at least one 1 when rolling an n-sided die n times: Math.round(1 - ( ((n-1)/n)^n -1 )*(n^n-1) )/n^n ...
15 views

### How to add a correction to the parameters in logistic regression s.t. the decision boundary is corrected?

Sometimes we would like to correct the decision boundary of a pretrained logistic regression model $p(y_{temp}=1|x)$, for example by multiplying by a prior in pursuit of adapting better to the ...
1 vote
31 views

### What is the meaning of “3 to 1 odds against success”?

I came across this passage while reading about forecasts, but I am not sure if my interpretation of the odds below is correct. I am interpreting it as there a 75% of success, is that correct? In ...
1 vote
35 views

### Interpreting logistic regression coefficients of a variable overall and levelwise

Context Let Y be a logical vector and X1 a factor with 3 levels. Since Y is binary, logistic regression is used. ...
122 views

### Probability of Lottery (TOTO)

I have just a question about probability/odds and combinatorics here. Context: In Singapore, we have a lottery called Toto. Buyers can pick at least six numbers, from 1 to 49. Group 1 prize odds is 1 ...
61 views

### Odds to probability transformation

The odds are defined as $\omega = \frac{\pi}{1-\pi}$, where $\pi$ is the probability of some event. How can it be shown that the back-transformations is given via $\pi = \frac{\omega}{1 + \omega}$?
1k views

### Why are log odds modelled as a linear function?

I think I already have the answer, however, I wish for some confirmation that I am not missing anything here. This sort of asks the same thing, but I want to double-check. Logistic regression can be ...
17 views

### Can we estimate the propotion of outcome (binary) variance explained by multiple predictors using summary statistics only?

A toy example: We aim to predict the onset of stroke by body weight and age. We know that: 1-SD increment of weight increases the odds of stroke by 20% i.e. standardized coefficient of regression ...
1 vote
90 views

### What happens to American odds when the point spread gets further from zero? [closed]

I am learning about American odds (moneyline odds) and point spreads. In Chapter 2 of Sports Betting for Dummies, I see: When the point spread on a game gets further from zero, the two moneyline bets ...
1 vote
81 views

### Are odds relevant for continuous random variables?

The odds of probability $p$ is $\frac{p}{1-p}$. Odds provide a measure of the likelihood of a particular outcome, calculated as the ratio of the number of events that produce the outcome to the number ...
1 vote
47 views

### Can we maximize the log of the odds instead of log of the probability?

As above. This question relates to all optimization formulations in statistics.
1 vote
723 views

### Interpret the AIC in logistic regression

I'm doing logistic regression in R with binary data (0's and 1's), sample size around 300 : Predicting 1 target variable (varp) If I use one independent variable ( varx), it's significant (p 0.03, the ...
1 vote
20 views

### Odds to probabilty and back- I am not getting same value!

I am using following formulae to convert between odds and probability: probability = odds / (1+odds) odds = probability / (1-probability) I am doing following ...
289 views

### How to get log odds from these results of logistic regression

I have performed logistic regression (using 'LOGIT') on variables from titanic dataset. The formula used is: survived ~ age + sex + pclass I have obtained results ...
1 vote
395 views

### Does the Elo system work with different expected value functions?

In many Elo rating systems, the expected value for player A with rating $R_A$ against an opponent with rating $R_B$ is $$E_A = \frac1{1+10^{(R_B - R_A)/c}}$$ The original Elo system is based on a ...
1 vote
92 views

### Calculating probability from multivariate logistic regression using odds instead of log odds

Question: is there a way to calculate probability from odds ratios instead of log odds ratios? I am trying to wrap my head around calculating probability from a multivariate logistic regression model ...
62 views

### Interpreting Odds Ratio (in an Interaction)

I need advice on the correct interpretation of an odds ratio of an interaction term. Both the mixed-effect logistic regression output is below as well as the predicted odds values, which I calculate ...
33 views

### How do interpret the odds ratio of a coefficient?

Building a logistic model with odds ratios, I have run into question I simply cannot figure out. Normally, the odds ratio of a coefficient equals how much the odds of y = 1 multiplies when x ...
51 views

### How to create a hypothesis test comparing two odds? [closed]

Let's say I have two odds, how would I conduct a hypothesis test with a 5% significance level?
1 vote
27 views

### Player based betting odds VS analysis based odds

there are two kinds of betting sites Player based odds sites (thunderpick.com , csgopositive.com , ...) analysis based odds sited (1xbet , bwin , and almost all of the huge betting sites) when you ...
5k views

### How to calculate probability of rain today given today percentage

Given this: If the probability of rain in a given day is 0.65, what are the odds that it will rain today ? Would I setup as P(A) = it rains 65% But with the missing today forecast, what and how would ...
1 vote
68 views

### Is a very large odds ratio from a contingency table an issue?

I computed an odds ratio from a contingency table (exposure/disease). My odds ratio ended up being 3329.044 which is ridiculously large. The reason it is large is because the prevalence of the disease ...
1 vote
481 views

### Odds Ratio for Interaction Terms in GenLin in SPSS

I have a generalized linear model using SPSS to determine the relationship between certain variables (sex, race/ethnicity, geographical area, etc.) and whether or not they use a computer. Also, we ...
137 views

### Interpreting the Odds Ratio of a logistic regression model

I'm currently working on building a logistic regression model with the aim of predicting whether a given stock index will go up or down the following day. The table below shows the 3 models I've ran ...
1 vote
99 views

### Double odds of one outcome, what should happen to the other outcomes?

When you have a binomial outcome, doubling the odds of one outcome halves the odds of the other outcome. E.g. if I have a weighted coin that doubles the odds of heads, it halves the odds of tails. If ...
48 views

### Determining the winner of a match given nothing but each team's winning percentage

Team A and Team B are playing a game against each other. This is the only information we have for each team: Team A has won 65% of their games this year Team B has won 59% of their games this year ...
48 views

### Are they cheating?

I'm trying to determine the probability that three students cheated on a recent exam. In a nutshell: What are the odds that three students sitting next to each other in a class of 22 could select (...
130 views

### How to interpret this logistic regression question?

This is from a DataCamp course. Try as I might, I can't seem to figure out how to break this down into explanations: The fitted coefficient β^1 from the medical school logistic regression model is 5....
1 vote
117 views

### Estimating/translating odds ratio for different percentile intervals

I have a question regarding a translation in odds ratio curve OR(x). More specifically, let's say we have an OR(x) which we get using logistic regression. We look at the interval bounded with 25% and ...