Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [model]

A formalization of relationships between stochastically (randomly) related variables in the form of mathematical equations. DO NOT USE THIS TAG BY ITSELF: always include a more specific one.

In mathematical terms, a statistical model is frequently thought of as a pair $(Y, P)$ where $Y$ is the set of possible observations and $P$ the set of possible probability distributions on $Y$ . It is assumed that there is a distinct element of $P$ which generates the observed data. Statistical inference enables one to make statements about which element(s) of this set are likely to be the true(s) one.

Reference: Wikipedia

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How is model stability defined?

I've read that multicollinearity can lead to a linear regression model being unstable. I came across this wikipedia article: https://en.wikipedia.org/wiki/Stability_(learning_theory), that basically says a model is unstable if the outputs vary…
adeevee
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How to put variables related by an IF condition in a model

The first variable is 'SMOKE' that indicate if the person is a smoker or not. The second variable 'Daily' is related to the first by an If condition: If the person is a smoker then does he smoke daily or not. How can I put these two variables in my…
user42987
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What are the advantages and contributions of quadratic relationship in a model?

I'm working on an article where investigators are looking for a relationship between mortality and individual-levels variables, area-levels variables in a population. Area-levels variables are an index of precariousness in the living area of…
Seydou GORO
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Qini curve and uplift

I am building an uplift model from clinical data and I would like to evaluate it and compare it with the performance of different models. For this, I plotted the Qini curve and obtained the Qini coefficients. Also, in parallel, I plotted the uplift…
Aurora
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Stock investment portfolio analysis. What model can I use?

A population consists of individuals with wealth $W$. They each form a portfolio $P$ which consists of relative weights corresponding to investments in $n$ assets. So if the portfolio for some individual is $[0.1, ...., 0.1]$ with $n = 10$, then…
Barnhold
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Modified gravity model of interaction between two communities

For a particular application I'm trying to specify a model for the level of contact between two communities, similar to modeling migration. I have no data on contact rates between communities, so there's no parameter estimation here - I'm just…
Macro
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Different parameters coming out as important from decision tree and logistic regression

I ran both logistic regression and decision tree model on the same dataset However, the parameters that come out as important in both vary. For example, the most important parameter in the decision tree (the 1st split of the tree) doesn’t even pop…
user100716
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How to model a multiplicative effect from this hypothesis?

Suppose we have outcome variable Y and two predictors X1 and X2, where X1 and X2 sort of come from a type of category. For example, X1 is the relationship score with friends and X2 relationship score with family. Not the same, but they reflect some…
NonSleeper
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Is it possible that the interaction effect is significant while the individual effect(s) is not?

Consider a simple model: Y = A + B + A*B Is it possible that coefficient for A*B is significant while that for A or B or both of them is insignificant? Either yes or no, can you tell what's the reason behind it?
NonSleeper
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Statistic model for removing bad data

Let's say I have a (ads live days, revenue) data set. The data set shows how much revenues each ads generates during the days it is live. ads1 generates 100 dollars during the 5 days when it is live. ads2 generates 200 dollars during the 10 days…
peipei
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GLMM Vs GAMM - log10 transform predictor variable to create linear relationship okay for GLMM?

I have a roughly exponential relationship between insect counts and distance along a growing tunnels, and need to examine the effects of different tunnel types as they relate to the abundance and distributions of insects along the tunnels, also…
Jeremy Jones
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Patient probability of showing up

I have patient visit data which includes: appointment date, clinic, appointment type (new or a review appointment), appointment priority (urgent, not urgent), age, gender, site, attendance status (showed up, did not show up). Given that the…
Suzan
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What statistical model to use?

I am looking for a what I think is probably a statistical analysis model. It could actually be a machine learning or fuzzy logic algorithm but my problem is that I know that I don’t know if it even exists or not. I think it must be quite a common…
Eds
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Too many significant variabels

I am doing some predictive churn modelling. I use around 250 independent variables (not all at same time). Those variables are transactional, demographics, external data etc. The database is fairly large, 100' plus. I am using backward elimination…
PRoglog
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Difference between significance and contribution

"What is the difference between "significance" and "contribution" of individual variable to a outcome variable? How to address this while creating a prediction model basically.I understand contribution made by a variable towards the outcome, which…
user52335
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