# All Questions

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4 views

### Increasing row numbers after TDM transformation

I have just started working on R text analysis and have the below issue going on. The dimensions for my Termdocumentmatrix increases from the original number of rows I started with the review data to ...
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### Why deep Q learning works?

In DQN we evaluate true Q value by formula $$r + \gamma \max \hat Q\left( {s,a,{w_{{\rm{targe}}t}}} \right)$$ And use the output of Network to fit it. Why we can use this formula to approximate true ...
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### Conceptual interpretations of predictive versus causal modeling

I'm a relatively non-technical clinician. And I recently came across an excellent paper paper (Schooling & Jones, 2018).The authors essentially implore biomedical researchers to use non-ambiguous ...
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### Logistic Regression in MATLAB glmnet always returns 0 vector as coefficients

I am using glmnet in MATLAB 2019a on my Macbook to do logistic regression. Algorithm: $log(\frac{\pi_i}{1-\pi_i})=\beta_0+X_i^T\beta$ $\pi_i=P(Y=2|X_i)=1-P(Y=1|X_i)$ Code: ...
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### Maximization bias in Reinforcement learning

I have a question about Maximization biased in RL. In Richard S. Sutton and Andrew G. Barto 's book page 156 which says maximization biased occurs when estimate the value function while taking ...
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### What is a good example of a hybrid data-set which has over 5000 entries? [on hold]

I'm looking for a dataset which has the following properties: Has more than 5000 entries Has both numerical and categorical data Is publicly available, free of cost I want to test an algorithm, and ...
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### How to edge weight the network to obtain shortest path and centrality measures

I am currently using networkx as follows to create a co-occurrence network where the weights represents the number of co-occurrences to calculate ...
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### Fitting nonlinear numerical model

I am reading a scientific paper that fits a numerical model to a timeseries (observations). The numerical model has a few free parameters, some of them linear and some are not, which the authors wish ...
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### error correction model for time series analysis data

Can somebody suggest a suitable Model for the Time Series problem below ? I have a variable x1 (numeric continuous), which is cyclically reset(say 3rd of every month ) and cumulative sum of which ...
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### How to use just one tree in a random forest with the R package randomForest?

With the R package randomForest, I can get a forest for classification. With the function getTree(), I can get each tree of the forest. Now, my question is how to do classification for a new input ...
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### Is each row of latent factors obtained from matrix decomposition (SVD) dependent on the other rows of the higher dimensional matrix?

I implemented a recommendation system using user-user interaction data, learning missing ratings through alternating least squares and matrix factorization, which as I understand it, adjusts and ...
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### Favored methods for overcoming selection bias (special attention to healthcare fields)?

I am frequently measuring the effect of behavioral health treatment interventions on outcomes of interest. However, comparing the relative efficacy of different types of treatment is tricky - more ...
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### Is this a random or a fixed effect?

I have a question about one of the variables in my study and whether or not it should be considered a random effect. I'm conducting a study of my school's 24 general learning outcomes (or "skills".) ...
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### Group level effects (odds ratio) - dummy coding vs. contrast

I ran a logistic model in R's brms, with a categorical variable (condition) with two levels as predictor. When interpreting the ...
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### Early stopping together with hyperparameter tuning in neural networks

Similar to this question (hyperparameter tuning in neural networks), I have a neural network with a similar list of parameters as the link above: ...
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### SSE not decreasing with increase in number of clusters

So as far as I know, SSE should decrease( or just never increases) as the number of clusters increases. I have an implementation of K-means where the parameter k was supplied as 5,10,15,20,25 and 30 ...