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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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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2answers
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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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1answer
67 views
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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2answers
25 views
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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2answers
50 views
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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1answer
133 views
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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3answers
208 views
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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1answer
294 views
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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1answer
25 views
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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1answer
64 views
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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2answers
86 views
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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2answers
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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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0answers
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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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1answer
52 views
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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1answer
111 views
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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0answers
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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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1answer
199 views
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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1answer
24 views
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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1answer
78 views
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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Interpreting the odds ratio for a proportion type regression coefficient - confidence intervals
So, while this post answers the question of how to obtain the odds ratio for intervals within a proportion variable, I was wondering is it possible to obtain confidence intervals for an interval in ...
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What is the probability of getting a 7 card straight with an 8 card hand, if using two decks of cards shuffled together?
Can someone please help me do this math?
I am trying to find the odds of the following:
Given that two decks of cards are shuffled together, and I am given (dealt) 8 cards. What are the odds that 7 ...
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1answer
13 views
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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199 views
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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0answers
34 views
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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0answers
30 views
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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0answers
38 views
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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2answers
121 views
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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1answer
41 views
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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35 views
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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1answer
37 views
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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1answer
801 views
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 ...
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Is a person probability of a plane crash reduced with the precence of a plane crash survivor?
If an average person has a probability of having a plane crash of 1/10 and another person boards the same plane, but this person already has had a plane crash so i guess this survirvor person has a ...
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why use an odds ratio instead of a proportion
I would appreciate your advice regarding a 'work' query, in that nobody at work can agree on what appears to be a very simple statistical analysis. I have changed some of the details to protect ...
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1answer
32 views
How to combine odds of an event happening with effects of said event
I have run an ordinal logistic regression. To keep it simple and to the point, I have found that customers with whom we perform a particular sales event are 1.5x more likely to upgrade. Of the ...
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1answer
182 views
calculating log odds of unemployment rate
Noob here trying to make sense of log odds calculation. I am trying to do some transformation on unemployment rate data. I read one paper that suggested performing log odds and this is denoted by:
<...
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2answers
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Interpretation of loglinear regression
Let's assume that gender is the only predictor in binary loglinear regression, in which we are predicting odds of getting paranoid schizophrenia (females are marked as 1 and males as 2). If loglinear ...
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1answer
38 views
What are the odds of predicting a series of coin tosses to a certain percentage?
So I'm stuck on a problem. It's related for some work I'm doing but I'll keep it simple here.
Here's the scenario: I flip a coin 11 times and I record the results without telling you what the results ...
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0answers
130 views
Probability of a certain card being UR, SR, R, or N
There are 200 packs in a box, and there are 3 cards in each pack (600 cards total) and you must buy one pack (3 cards) at a time. A pack can contain: An UR (10 total), a SR (24 total), a R (192 total),...
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2answers
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What type of statistical test should be used to compare successes of two treatments?
Say I have two treatments, "hot" and "cold".
I care about a certain outcome, say "success".
I have data on the number of successes out of, say 100 trials in the "hot" treatment.
Similarly, I have data ...
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1answer
146 views
Calculating Odds of Getting a Sample w/ a Specific Standard Deviation
Trying to calculate the odds on something and was getting myself confused. I'll try to summarize into a simple problem with made up numbers.
Say a cannon fires projectiles with a population mean of ...
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1answer
38 views
odds of avoiding a one rolling two dice two rolls in a row
in order to avoid losing my backgammon match, I had to avoid rolling a one on both of two successive rolls with two dice on each roll. If I rolled a one once or double ones I was ok, I just couldnt ...
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1answer
123 views
Odds Ratio decreases after every variable entered
I ran a logistic regression with only 1 independent variable and came with an 18.59 odds ratio with a c statistic of .50.
After adding 4 variables that independent variable odds ratio decreased from ...
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1answer
64 views
At what point in a logistic regression does a predictor become significant in predicting outcome?
Say we have a logistic regression with outcome equal to a women's pregnancy resulting in a birth =1 and loss=0. The predictor variable is age ranging from 22-50, the Odds ratio point estimate is .819 ...
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1answer
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Why is relative risk not valid in case control studies?
I'm getting my information from:
http://sphweb.bumc.bu.edu/otlt/mph-modules/ep/ep713_analyticoverview/EP713_AnalyticOverview5.html
It says that in a case-control study, you can not compute the ...
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Who has done research on marital status? I am running a logistic regression analysis
I have NLSY97 data and specifically look at a cross-section (2013 data), where respondents are between 28-32 and who got married and who didn't. I want to see which of the independent variables are ...
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773 views
What does it mean when your adjusted odds ratio is higher than your unadjusted odds ratio (logistic regression)?
My adjusted OR for my variable of interest from my multivariate logistic regression is around 3.20. My unadjusted OR from my univariate logistic regression for my variable of interest is 2.75. This is ...
