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).
0
votes
2answers
21 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/...
1
vote
2answers
43 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 ...
-1
votes
0answers
15 views
How do I get an odds ratio using Mcnemar in R? [duplicate]
I have pre and post test data evaluating the effectiveness of a lesson about how to help friends who are being bullied. I am trying to see if more students know how to help a friend being bullied ...
0
votes
1answer
59 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 ...
1
vote
3answers
78 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;
...
3
votes
1answer
166 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 ...
2
votes
1answer
21 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 ...
0
votes
1answer
62 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 ...
1
vote
2answers
80 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 ...
2
votes
2answers
54 views
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 ...
1
vote
0answers
9 views
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 ...
0
votes
1answer
49 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 ...
0
votes
1answer
68 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 ...
1
vote
0answers
20 views
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 ...
1
vote
0answers
37 views
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.
...
1
vote
1answer
134 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 ...
0
votes
1answer
23 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 ...
0
votes
1answer
69 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 ...
0
votes
0answers
12 views
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 ...
0
votes
0answers
17 views
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 ...
0
votes
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?
0
votes
0answers
29 views
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 ...
1
vote
0answers
166 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 ...
0
votes
0answers
33 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 ...
1
vote
0answers
29 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 ...
0
votes
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?"
1
vote
2answers
111 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, ...
0
votes
0answers
45 views
Aggregating Odds of Logistic Regression Predictions
I currently have a logistic regression model that predicts a win or loss for a game, based on data from a player. The accuracy is 83%. So by looking at a players past few games, it can predict which ...
2
votes
1answer
40 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 ...
0
votes
0answers
33 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 ...
1
vote
0answers
302 views
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 ...
0
votes
1answer
34 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 ...
1
vote
1answer
631 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 ...
0
votes
0answers
24 views
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 ...
3
votes
0answers
56 views
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 ...
3
votes
1answer
31 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 ...
0
votes
1answer
171 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:
<...
1
vote
2answers
105 views
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 ...
3
votes
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 ...
1
vote
0answers
121 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),...
1
vote
2answers
49 views
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 ...
0
votes
0answers
143 views
About adjusted odds ratio
in my binary logit model, I have got adjusted odds ratio of .744 for a predictor variable named Age group of pedestrian. There are four age groups. They are less than 18 years, 18-40 years, 40-60 ...
4
votes
1answer
139 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 ...
1
vote
1answer
36 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 ...
0
votes
1answer
108 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 ...
1
vote
1answer
63 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 ...
5
votes
1answer
2k views
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 ...
1
vote
0answers
48 views
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 ...
0
votes
0answers
678 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 ...
1
vote
0answers
52 views
Proportions are telling a different story than odds ratios
Context
Stimuli: 2 different designs (A, B)
Outcome: task success (binary y/n)
n = 100
Between-subjects (50 Design A; 50 design B)
Interpreting the proportions suggests there is no real difference ...
