# All Questions

19 views

### How to stack a convolutional autoencoder?

I am trying to figure out as to how to stack a convolutional autoencoder (CAE)? Consider a convolutional autoencoder (CAE) (using MNIST data, 28x28 input dimensions): ...
14 views

### Hausman test for 2SLS vs 3SLS

Can we do a Hausman test for 2SLS vs 3SLS? I know that we can do a BP test for the cross-equation correlation of errors, but what should the null and alternative hypotheses of a Hausman test be?
4 views

### how to generate data stream from a flat file (.arff). [on hold]

I have a data set in arff format. Hope anyone can guide me on how to generate stream from this flat file.
31 views

### How to interpret the residual colors on a mosaic plot?

This is a mosaic plot of contingency table dataset HairEyeColor described here. How do I interpret the colors representing residuals? What is the difference ...
19 views

### Eliminating a nuisance parameter in likelihood ratio test

I am having an argument with a co-author about how to eliminate a nuisance parameter in a simple likelihood ratio test and am hoping that the community helps us settle it. Our data $\mathbf{x}$ can ...
19 views

### Predictive model decision tree [migrated]

I want to build a predictive model using decision tree classification in R. I used this code: ...
20 views

### Endogenous interactions in nonparametric instrumental variables

I'm interested in estimating a model along the lines of $$pr(y==1) = g^{-1}\left(f(x_1,x_2)+X'\beta\right)+\epsilon$$ where $g$ is logit and $f$ is some smooth function. I'm using GAM's in ...
8 views

### Maximizing mean reversion of residuals

I'm regressing multiple stationary time series in order to maximize the mean reversion of the residuals. I fitted a model via OLS, and discovered that the residuals had a strong negative ...
14 views

### Probability of selecting exactly 2 members of a group of 7, out of 35 people, if 3 people are picked

There are 7 friends A, B, C, D, E, F, and G that belong to a classroom of 35 students. Three students are chosen from the 35. What the probability that exactly two of the group of friends is chosen? ...
19 views

### Bayesian Mixture Model Gibbs Sampler for two linear relationships

I am attempting to use a Gibbs Sampler to model a mixture of two groups, where the group membership is defined by a linear relationship conditional on x. Both groups have the same slope and intercept, ...
13 views

### Jeffrey's Prior for normal distribution with mean = 0

How would I go about calculating Jeffrey's Prior for a normal distribution with mean = 0, So far I get: But then don't know where to go next. Any help much appreciated
7 views

### Successfully simulated physical process, matches truncated/incomplete data…now what?

What's Being Simulated I have data from a device that tests a physical process. The data are independent Bernoulli trials. Each test series yields a distribution of these trials with different N and ...
16 views

### How many different arrangements, when selecting 2 out of 5 objects? [on hold]

How many different arrangements are there, when selecting 2 out of 5 objects? In this question what should I use - nPr or nCr?
2 views

### Are pooling layers added before or after dropout layers?

I'm creating a convolutional neural network (CNN), where I have a convolutional layer followed by a dropout layer and I want to apply dropout to reduce overfitting. I have this feeling that the ...
13 views

### I am new to matlab and I have noticed that many matlab programs start with the code global data. What does this mean? [on hold]

How does the code global data support the rest of the codes in a matlab program?
16 views

### Estimating confidence intervals on count data from classifier output on varying populations

I have a widget factory which produces a varying number of widgets each day. Every day, I need to report the number of faulty widgets. But the proportion of faulty widgets is expected to change every ...
24 views

### Modeling different lag structures

I know there are various information criteria that can be used to compare model specifications, including those with different lag structures. I can easily compare the Akaike Information Criterion ...
15 views

### shall I add all correlated variables in a mixed effect model?

If I have a mixed effect model case with various predictor variables. If some of the variables are correlated; is it better to add both correlated variables to the model? or shall i take out one of ...
10 views

### Pooled T-Test for Binary Observations?

I'm trying to compare two populations with binary variables, and I'm not sure how to do a t-test to compare them in R. I think I'm supposed to do a pooled t-test, but all of the methods I'm finding ...
8 views

### Compute confidence cutoff for scatterplot

I have data collected from two different individuals for different treatments, like this: ...
26 views

### Berry-Esseen Theorem with Continuity Correction

Given independent but non-identical random variables $X_1, X_2, \ldots ,X_n$ with $E[X_i]=0,$ $E[X_i^2]=\sigma_i^2=1$ and finite absolute third moments $\rho_i=E[|X_i|^3].$ Let S_n = {{\sum_{i=1}^n ...
29 views

### Doubt on the Johansen Procedure and normalization of the cointegration matrix in R

I'm a beginner at Econometrics, and I'm trying to learn the main econometric techniques in R. My doubt is on how to normalize the cointegration matrix to ensure ...
18 views

### Subsetting dataframe conditions on factor (binary) column (vector in R)

I have a sequence of 1/0's indicating if patient is in remission or not. Assume the records of remission or not were taken at discrete times. How can I check the Markov property for each patient, ...
34 views

### Prediction interval for lmer() mixed effects model in R

I want to get a prediction interval around a prediction from a lmer() model. I have found some discussion about this: ...
19 views

### Why is $\sin(\theta)$ not U-estimable in this example?

For completeness I give the definition of being U-estimable: An estimator $\delta$ is called unbiased for $g(\theta)$ if $E_{\theta} \delta(X) = g(\theta) \ \forall \theta \in \Omega$. If an ...
16 views

### How to compare two PROPORTIONS if you don't have 'n'?

Have data in this format: | A | A' | B | B' | |-----|-----|-----|-----| | 0.4 | 0.2 | 0.4 | 0.3 | | 0.3 | 0.3 | 0.3 | 0.5 | | 0.1 | 0.2 | 0.6 | 0.2 | Note ...
8 views

### R: hclust() calculating variance within each cluster

I've got a distmatrix where the element at [i,j] describes the cosine distance between variable i and variable j. When I use hclust(), and then I use cut.tree to make K clusters, then I would like to ...
8 views

### reversed output in RandomForest predict function in R

I am using the RandomForest package in R to do classification. I use this in combination with GIS data and so use the package "raster" as well. I run the RandomForest and everything seems fine until I ...
8 views

### r : Why is findAssocs() not working? (at all) [migrated]

findAssocs() is not working, as is seen below. "Lucid" and "dreaming" occur together quite often in the book. The corpus is a single document, the text version of a book. Does this function require ...
7 views

### Heuristics for streaming data matching [duplicate]

I have an index composed by thousands of documents. Slightly modified copies of those documents are sent to my application in small chunks, and I need to check, from those chunks, which document has ...
24 views

### Heuristics streaming data matching

I have an index composed by thousands of documents. Slightly modified copies of those documents are sent to my application in small chunks, and I need to check, from those chunks, which document has ...
44 views

### Which machine learning model is applicable to the following case

I want to build a model that recognizes the species based on multiple indicators. The problem is, neural networks (usually) receive vectors, and my indicators are not always easily expressed in ...
22 views

### Describing trend magnitude or detecting trends

I have time series data. One observation per time period, about 10 observations or so. When describing the data (I am interested in descriptive statistics), I'd like to say that there is either a ...
21 views

### In intuitive explanation how does GLAM (Gray Level Aura Matrix) works? [on hold]

and i look for a simple example about GLAM (Gray Level Aura Matrix).i need your help.
21 views

### How to create a multidimensional data structure in R as input to kernlab's ksvm()

This is a revision/rephrasing of my question originally posted on stackoverflow. How should I create the training/input dataset for a ksvm model with multi-dimensional input data? The process for ...
27 views

### How to generate matrix with Student t-distribution? [on hold]

I am trying to generate matrix-valued samples from a t-distribution. What I found so far is the multivariate t-student distribution but it deals only with vectors. There is nothing about matrix-valued ...
9 views

### Categorical data and different analyses

Why does categorical data have different tests? I know there are many tests for categorical data such as a crosstabs or Chi-Square but why does the data use different tests?
14 views

### Why the prediction of multivariate GARCH is just a line?

I'm doing multivariate GARCH analysis between two stocks, like many examples you can find online. The fitting goes very well but I'm confused by the prediction part. Why the forecasted conditional ...
11 views

### Unit weighting for linear composites / regression

Cohen (1990) mentions a regression that I have not heard about before. Here is how I understand his description: Standardize the dependent and the independent variables Regress the standardized ...
16 views

### An IR evalualuation metric that only measures the rank of results?

I am working on a little text clustering problem, and trying to figure out how to evaluate the results. I came up with the following idea that I though fits pretty well with the specifics of the ...
7 views

### Efficiency of biased and unbiased estimators [on hold]

Population of a certain county are 80% urban and 20% rural. Urban voters tend to vote democratic 70% and republican 30% of the time. Rural voters tend to vote republican 75% and democratic 25% of the ...
26 views

### What is the difference between buckets and bins?

When calculating a histogram we do data binning, or group a number of more or less continuous values into a smaller number of "bins". But in bucket sort we set up buckets and assign a bucket to each ...
24 views

### How to remove normalization function on data? [on hold]

I currently have my data scaled between the range of 0 and 1 using the following normalization function in R: ...
6 views

### R-Studio summary page independent variable percent [on hold]

What in R Studio's summary of data shows percent of the independent variable if the dependent Variable is 0? For instance, my Y axis is an independent variable and my question is asking if the ...
10 views

### Improve rate estimates of geo. events by other attributes?

I have somewhat rare events (at given times) at geographical locations. I also have a lot of static data about each micro-region. Some of the static data is likely to be correlated with the true event ...
5 views

### Guarded Discrete Stochastic network to solve CSP

There is a lot about NPL and vision systems but not a lot about constraint satisfaction problems (CSP). I have been digging around but I could use some guidance on how to use neutral network to solve ...
15 views

### Why is removeSparseTerms() not doing anything? [on hold]

This has me very, very puzzled... removeSparseTerms() is not removing any terms. ...
31 views

### What test is appropriate for my data set?

So my data is on feedback students receive during their 4 years at university. I sent out a questionnaire and there are 23 questions in total, each question is looking at the perception and value of ...