# All Questions

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### Bayesian liability threshold model

Let $\bf{y}$ denote a vector of binary data, such as whether a group of individuals suffer from a particular disease, and let $\bf{X}$ denote a matrix of potential predictors, including an intercept ...
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### Identifying anomalies multiple time series using statistical methods

I am trying to detect anomalies from a Time Series sequence, that is calculated as an aggregate count of multiple unique Time Series'. For example, in the graph below: We have aggregate counts shown ...
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### Example of random process with negative variation

I study about random processes. Let us have $\{X_1, X_2, \dots X_n\}$ observations. I learned, that in stationary time series the sample autocovariance function is defined as  \widehat{γ}(h)= \...
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### Why is PCA (using sklearn library) increasing the size of my dataset?

I used PCA on the Fashion MNIST dataset, with the intention of reducing the size of the dataset. ...
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### how to use categorical variable with continuous variables in a EM mixture model

I'm trying to use the mclust and flexmix packages in R to do unsupervised clustering of my data which has both continuous variables and categorical variables. I'm having a hard time understanding how ...
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### Confidence Intervals 111110 [on hold]

If a sample of 30 wheels has a mean of 60 cm, give a 95% Confidence Interval for the mean diameter of the wheels from the factory. Enter your answer as an interval [ a, b ] where a, b should be ...
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### How can I combine multiple variables of different scales [on hold]

I have several factors that I want to combine into one. But each factor is of a different scale. Factor A goes from 0-1, factor B goes from 1-10, factor C goes from 20-40, etc. I don't want the ...
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### Finding the MGF, distribution, and parameter of a random variable

I am currently working on the following problem from my textbook Introduction to Probability by Blitzstein and Hwang: Judit plays in a total of $N\sim Geom(s)$ chess tournaments in her career. ...
20 views

### Are Python classes in Spark notebooks beneficial or common in the data scientist community? [on hold]

Being a software developer, I am coming from an object-oriented programming background, and I think in terms of classes and objects. I am currently working on a ...
8 views

### Applying settlement and Regional fixed effects

I'm reading a paper by Gyöngyösi and Verner (2019), and noticed that the authors have included fixed effects at the settlement (seems to be akin to village/town) and at the region level, in a number ...
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### Too large standard errors of parameters from the covariance matrix when fitting data using curve_fit

I have some troubles when try to fit my data using curve_fit. I don't really know where I am wrong: in code or in math. First, I have too large variances which I get from the covariance matrix: ...
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### Using text and images for training, but only images for inference

I am working on a problem with data like: $\{X, T, y\}$, where $X$ are images, $T$ is useful information about those images, and $y$ are image labels. I would like to build an image classifier that ...
12 views

### Neural Network unable to learn [on hold]

I am following trask's article to build a bare bone neural network in Python. Though he builds 1 layer Network (that maps 3 inputs to a single output) and a 2 layer network (that has 3 inputs, 4 ...
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### AutoEncoder Reconstruction error for Anomaly Detection

I'm building a convolutional autoencoder as a means of Anomaly Detection for semiconductor machine sensor data - so every wafer processed is treated like an image (rows are time series values, columns ...
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### How to carry out the score bootstrap?

I want to translate the "score bootstrap" that Kline and Santos (2011) propose into R code. The method is described on page 6 as follows. STEP 1: Obtain the full sample OLS estimate $\hat\beta$ and ...
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### Explaining Profitability in Banks Using Panel Data Dynamic/Fixed Effects Model

I am currently looking to study the profitability of banks. My 4 independent variables, which are taken from banks balance sheet, are just financial ratios. My time is 13 Years, and I have 21 banks. ...
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### How to compare a model with my data [on hold]

using R I have to compare a model, that is the Fitt's law, with my data. In particular the Fitt's law states that MT = a + b × log2(2D/W), with MT is the time needed to perform a task, a and b being ...
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### How to tell if difference in f-score is significant?

I have $N$ data points, each of which has an associated label that is either $0$ or $1$. For which data point I know the true label. Say I put all true labels in a vector $t$. Next I ask Alice to ...
26 views

### Uncertainty Quantification in Time Series Analysis

The stock market value of the data point connected by the red line is predicted by linear regression using market values as well as Twitter sentiment data and more in a certain period of time (red ...
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### How to estimate conditional CDF using python StatsModels

I am using statsmodels '0.10.1' to obtain conditional CDF of a 2 variable problem. ...
9 views

### How to compute RSquare from GLS regression in a Fama Macbeth procedure

I am trying to compute the RSquared from the Fama Macbeth procedure using GLS regression, but for some reason I get negative values, so I was wondering what the problem might be. The Fama Macbeth ...
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### German credit dataset : interpretation of checking_status feature

I am struggling to understand the meaning of some features of the german credit dataset (https://archive.ics.uci.edu/ml/datasets/statlog+(german+credit+data)). I am particularly interested in, the ...
22 views

### How can I generate a completely balanced combination

Attaching a code that generates unique combinations of 8 letters but, it still lacks a condition wherein all letters should have equal counts per column. For my code, basically, letter a to h should ...
45 views

### How does random variable nesting in GAMs work (mgcv)?

Consider me very new to the world of GAMs, I am actually using it out of necessity rather than by choice but I thought it could be a chance to learn something new anyway. Originally I had hoped to ...