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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726 views

Why use odds and not probability in logistic regression?

Why would we use odds instead of probabilities when performing logistic regression?
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25 views

Odds ratio confidence interval and p-value do not agree [closed]

I calculated an odds ratio of 0.125, p-value (alpha 0.05) = 0.0378. However, the 95% CI crosses 1. (0.0143, 1.0635). I am wondering how I can reconcile this difference. Ideally I would like to report ...
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29 views

Question regarding odds and odds ratios

I wonder if having multiple groups (race: white, asian, black, hispanic), can I calculate odds ratios for these groups. The data are encoded as nominal variables (0,1,2 etc.) I have a $4 \times 2$ ...
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1answer
48 views

Odds on dice with 5-sided die

If a die with only 5 sides was tossed 5 times, Would the odds of a "5" coming up 5 times in succession be .2 to the fifth power or .00032? Would the odds of any one number coming up 5 times be ...
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1answer
25 views

How do I calculate the tipping point of over/under odds in Football?

I am trying to understand how game odds work. One scenario I came across was the over/under scores for football (soccer) games in the form of a table like this: ...
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1answer
22 views

How to compare predictive power of sports odds

For my MSc Thesis I would like to compare the predictive power of classic bookmakers on the one hand and a betting exchange on the other. I have a lot of data on both types of betting, mostly on ...
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0answers
17 views

Probability of Multiple Events Occuring

I was just wondering if you could point me in the right direction in calculating the best way to calculate the odds of two or three events occuring in order to work out the probability in percentage? ...
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1answer
32 views

How to derive likelihood of an event from probability values? What's the difference/relation between odds and likelihood?

I am trying to understand the relationship between probability, odds, logit values and likelihood. Is there any?
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1answer
128 views

A statistical interaction is significant, but the author denies it. Why?

I am evaluating a journal article regarding its statistical interactions. The article is trying to establish a relationship between less-tight control of blood pressure and progression to severe ...
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1answer
64 views

Does logistic regression determine the direction of the association?

I've conducted a logistic regression in which a binary outcome was the dependent and some continuous factors were entered as independent variables. First: Can this model determine that the ...
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0answers
10 views

nested logit interpret coefs

how do I get the odds ratio from a coefficient of a nested logit. I know for multinomial logit, the exp of the coeff of a binary independent variable is the odds ratio. is that true for nested logit?
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1answer
33 views

Odds of impostor?

Assume I left a hotel room key at the concierge to be picked up by my friend John Doe. The key is put in an envelop, "John Doe" is written on the outside of the envelop, and the people at the ...
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0answers
23 views

Does having a significant result from chi-squared test for independence also means that the odds ratio is significantly different from 1?

Suppose I have 2 by 2 contingency table. I performed Pearson's chi-squared test for independence and the results are significant. Does that mean the odds ratio that I calculated based on the 2 by 2 ...
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2answers
258 views

Ran a logistic regression and calculated the probabilities but they appear too high

I ran a logistic regression in R using driving data from about 10,000 people. The model included age, years of driving experience, as well as 4 driving test results. The dependent variable was whether ...
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2answers
289 views

Probability that Secret Santa arrangement will result in perfect pairings

So, we had Secret Santa at work. We're 8 people. We each took turns and pulled a small piece of paper from a bowl with a name on it. The only rule : If you pull your name, you have to put the piece ...
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0answers
25 views

Office raffle pooling (random stats question)

I have a question that has been bothering me about the statistics of a raffle drawing we had at a holiday party today. There were 65 prizes and 150 participants. Each time a winner is selected, that ...
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2answers
36 views

Logit: why aren't my exponentiated coefficients equaling my odds ratio (for nominal predictors)?

I'm running logit in JMP. My understanding is that if you exponentiate the coefficients, you get the change in odds ratios from a 1 unit change in X. This works perfectly for continuous independent ...
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1answer
288 views

Odds made simple

I am having some trouble in understanding odds, and I would like just a basic explanation for how to interpret them. I have found various posts related to odds but most of them are more complex than ...
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1answer
63 views

Significance between odd ratios

I´m fairly new to the tools of statistics and I need some help. I´m working in R. I have a list of students, their age, sex, test results(continuous variable) and education (a categorical variable. 0 ...
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1answer
84 views

Relationship between logit and odds ratios

Alright so I am trying to sort out exactly what a logit is in terms of a ratio... I understand that : $logit(p) = log(\frac{p}{1-p}) = \beta$ and that $exp(\beta) =$ odds ratio =$ ...
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1answer
133 views

How to calculate chance of occurrence based off a sample

I found this interesting study that shows basically how much more likely you are to get divorced based on certain factors of your marriage. It goes down to the cost of your wedding ring. See here ...
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31 views

Interpretation of odds ratio in logistic regression

In the study of birth weight (low or normal) of a child, the "birth term" of the child has been considered as a risk factor. The birth term has two categories: premature and full-mature.The following ...
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0answers
41 views

Comparing odds ratios - conditional or unconditional MLE

When comparing log(OR) from two contingency tables using Z-test should I use conditional maximum likelihood estimate of odds ratios (as given by fisher.test in R) or simple unconditional?
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1answer
152 views

statistics of airline crashes

Ive been going back and forth with a friend of mine on the issue of airline crash statistics. The concept of "independent variables" seems to be the biggest disagreement between us, so I was hoping to ...
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21 views

Different Odds ratios in SPSS [duplicate]

I've got a dichotomous dependent variable = 5 year overall survival (dead=0, alive=1) and I've got a dichotomous independent variable = presence of inguinal metastasis (none=0, present=1). When I run ...
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69 views

Calculation of odds accuracy - what am I measuring here?

Disclaimer: I am an amateur at statistics and I’m trying to learn by my own. Please bear with me if the question below sounds like utter nonsense to you guys. In an experiment where you have Team A ...
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15 views

Odds Ratios and Seasonal Pattern

I want to interpret Odds ratios with weather temperature through a line or any kind of a graphic. Do I need to re-scale Odds and temperature? What do you recommend?
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1answer
56 views

Natural Resource Management: How do I estimate the odds ratio and confidence intervals from model-averaged estimates?

I'm currently working on a model selection analysis in the field of natural resource management. My research question is: what variables are important to an avian species nest site selection. My ...
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1answer
94 views

Odds or Odds Ratio terminology?

I am having a bit of a tough time with some logistic regression terminology. I have performed a multivariable logistic regression analysis where I have regressed a binary variable (death, where 1 = ...
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1answer
93 views

Probabilities vs. Odds Ratios

Suppose we know that the probability of a female getting into a program are $p=.7$ and $q=1-.7=.3$ for males. Then we know: $$\mbox{odds}(\mbox{female}) = .7/.3 = 2.33333$$ ...
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26 views

Relating odds to percentages

Suppose I have a logit model with the response variable admission. The odds ratio for the one of the variables, test score, is 1.228. Then for 1 unit increase in test score, the odds of being admitted ...
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3answers
139 views

If each airline flight has a 2.6 in 1,000,000 of an accident and a person goes on 1000 flights, what are the odds for that person?

I would like to understand the way to calculate this particular problem. I understand that each flight still has a 2.6 in 1M chance of accident. But a person who takes more flights would seem to be ...
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1answer
31 views

What are the odds of only winning a lottery once when there is a 1 in 3 chance of winning with each draw and you have 20 draws?

Lottery chance to win is 1 in 3. I have 20 changes. I only win 1. What is the statistical probability of this outcome?
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61 views

Just curious of the odds of this happening

Was having lunch with a lover on the boardwalk and he pulled a random couple off of the boardwalk to have lunch with us. As we were talking, we discovered that both men had the same birthday, and the ...
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0answers
25 views

Is ıt possible to fit a proportional model by hand?

I was asked to solve the question below by hand as a homework. I did it in R, but I think it is impossible to build the model by hand as one needs to conduct numerical analysis to obtain the betas. Am ...
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2answers
75 views

The reason for saying “5 out of 10” instead of “1 of 2”?

I'm just being curious, i have seen on some places, statistical results where they give them in form of "10 of 100.000" or "5 of every 10". I don't have any statistical knowledge over my personal ...
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0answers
87 views

Calculate betting odds algorithm book [closed]

I'm just wondering, is there any book with good explanation of betting odds calculation algo. Good example is, tennis or poker. After each shot, or next opened card, the odds are changing. And I want ...
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0answers
31 views

Mean residual lifetime divided by odds of survival?

Is there a name for the mean residual lifetime divided by odds of survival? Does it have an intuitive meaning or interpretation? Example: $P(X=\{0,1,2,3\}) = (0.40, 0.30, 0.2, 0.1)$ ...
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2answers
2k views

How can I explain proportional odds models to a layman?

I'm writing an interdisciplinary research paper and I'm having some troubles in clearly explaining my findings. In particular, I applied a proportional odds model with one regressor $x$ and three ...
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0answers
301 views

Differences between logistic regression parameter estimates and Cox-proportional hazard parameters

We have been working on a survival analysis. We are examining tree seedling survival over a decade with annual to biannual census intervals. We have been using the package coxme in R for a mixed ...
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5answers
3k views

How to convert sport odds into percentage?

I am wondering how to convert sport odds to the percentage format. There's this example: ...
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1answer
689 views

Interpretation of Odds in Probit Regression

Logistic regression is concerned about modelling log-odds, i.e. logits. Hence, the odds of the computed probabilities can be interpreted accordingly. However, when estimating a probit model, one could ...
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3answers
59 views

Relationship between $\beta_1$ and odds in simple logistic regression

I am taking a course in logistic regression, and currently my class is about to finish our discussion about simple logistic regression. My professor said that the following statement is correct: ...
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2answers
130 views

Odds vs. Probabilities (Confusion)

In logistic regression, I know that Odds and Probabilities are two different things, but still I can't distinguish between them. I will be very grateful for your clarifications.
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1answer
56 views

What are the odds of this happening?

There is a list of exactly 94 names on it. One person randomly picks 5 names on the list and doesn't show them to anyone. Another person picks just 2 names on the list. What are the odds that one of ...
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0answers
49 views

Interpretation of logged term in logit (generalizing previous answers)

I have a logistic regression model, where one of my variables is logged. It is of the following form: $\ln(\frac{p}{1-p}) = B_1\ln(X) + B_2Y + ... + \epsilon$ , where $\epsilon$ is an error term. I ...
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0answers
101 views

Interpreting Odds Ratios for Natural Log transformed Variables

For those who are using Stata the following command clogit Y X,or would produce the odds ratio from the Conditional logistic regression which is the change in the ...
3
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1answer
109 views

Looking for a layman's explanation of how to manually calculate log odds?

I will start that I am not as math oriented as I would like to and could use a layman's / non-staticians explanation walk through of how to calculate the log odds. I am reading Hosmer, Lemeshow, and ...
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0answers
62 views

Odds of a team winning a sports match given full history

Assumptions: The teams never change The teams don't improve in skill The entire history of each team's performance against some subset of other teams is known For example: I have a long list of ...
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2answers
83 views

Do odds increase over time based on brute force?

Attempting to understanding a statistical concept which I'm positive is basic stats, but that I currently don't understand. Say that there's a one in ten million likelihood of an outcome happening ...