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3 views

Sample Size Calculation considering Gradual Improvements to Treatment Group

I have an experiment with two equally sized groups. These groups contain machines and the metric being measured is the failure rate of the of the groups. In a typical experiment setting, the test ...
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0answers
3 views

Omitted variable bias in ordered logistic regression query

Including too few variables in OLS regression means that the coefficient estimates can be biased, e.g. if we aren't controlling for a variable in a model that should be there, it is instead captured ...
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0answers
2 views

How to take actions at each episode and within each step of an episode in deep Q learning?

In deep Q learning, we execute the algorithm for each episode, and for each step within an episode, we take an action and record a reward. I have a situation where my action is 2-tuple $a=(a_1,a_2)$. ...
1
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0answers
5 views

Interaction term intuition

Say if we had a case: $y=α+βmale+βeduc+ε$ $y=α+βmale+βeduc+βmale*educ+ε$ let's say that both male and educ are indicator variables. What exactly does the interactive term mean in plain English, ...
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0answers
8 views

Machine learning algorithm for finding most similar entries in dataset

I have a pandas Dataframe, which has data as structured below. ...
0
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0answers
3 views

The upper bound of expression

The positive semi-definite concept can be extended to any complex matrix $A$, complex matrix $A$ is called positive semi-definite if $Re[x^*Ax]\ge 0$ where $x\in\mathbb{C}^n$ is any nonzero complex ...
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0answers
10 views

Lasso regression shrinking all coefficients to 0 even if there is a clear relationship in OLS, in R

So I am having an issue where all coefficients are at 0. I am trying to find the factors that explain the S&P 500 returns. In my lasso model outcome variable $Y$ is the monthly returns of the ...
0
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0answers
3 views

How to calculate similarities/distances and conduct cluster analysis from contingency table

I have an 18x25 contingency matrix, rows are behaviors observed and columns are environmental features. I conducted a correspondence analysis via the CA() function in R and then clustered using the ...
0
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0answers
5 views

Creating Predictions From Base Regressor Models in a Boosted Machine

So I'm writing my own implementation of AdaBoost using chapter 10 of Elements of Statistical Learning. The pseudocode given in the book lists how to make the algorithm for a classification problem, ...
0
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1answer
20 views

propability when Y = ln(X)

If $Y = \ln(X)$ and $P(Y) = 0.55$ Can i say that $P(X) = e^{P(Y)} = e^{0.55}$ ? ($P(Y)$ is the probability of $Y$, and $P(X)$ is the probability of $X$)
1
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2answers
16 views

Can I compare two conditions with one sample t-test?

I am reading a paper and in the methods section of the supplementary material, they describe how they compared the two conditions (stimulated and unstimulated) by saying. Statistical analysis of ...
1
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1answer
20 views

Why does the predictive distribution involve no $\textit{new}$ data?

Given data $(\textbf{X,Y})$, a Gaussian Process $\textbf{F}$ that is normally distributed and weights $\textbf{W}_1$ and $\textbf{b}$ also from a distribution, how come is the following distribution \...
2
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1answer
10 views

How many hidden neurons are necessary to approximate a linear function?

Let's assume we have a multilayer feedforward network with one hidden layer. The hidden layer must consist of at least two neurons with logistic activation function. How many hidden neurons are ...
0
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0answers
8 views

Long term time-series prediction for non-stationary but regular water flow data

I am looking at a very interesting time series dataset for the volume of water flow through some groundwater sensors. Our goal is longer term prediction of water levels, such as 1 - 5 years in the ...
1
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0answers
5 views

Is it possible in a forest plot all negative confidence intervals sum to a positive range,?

For example in that case, all confidence intervals are negative BUT the sum is in positive range (-37.62 to 0.5), which I don't understand. If there is anybody knows the explanation I would be ...
0
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0answers
9 views

How to Build a Pairwise Ranking Model Using Tree Based Algorithms?

Building a pairwise ranking model using linear algorithms is easy to understand. We just need to do pairwise transformation on the original data and create 0/1 labels. Then feed these pairwise ...
0
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0answers
14 views

Grouping individuals into households

I have a couple of datasets that contain results of tests, saying whether or not they have a disease. For those that are infectious, I have test results of children in their households. From this, I ...
0
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3answers
26 views

I think my data is heteroscedastic but I would like another opinion if possible?

Thank you for looking at my question, I've been driving myself a little crazy over it today! I have run tests for the assumption of homoscedasicity however I have been deliberating whether the ...
0
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0answers
4 views

Analysis of reaction time data along two dimensions

I just started thinking of an experiment where stimuli change according to two variables: eg., color and shape. Let's suppose that there are two objects presented one after the other (Obj 1 and Obj ...
0
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1answer
10 views

Regression - how to implement independent variables that are ratios and sum up to 1?

I'm learning by building models on UCI datasets and I've found interesting and difficult (for me ;-)) dataset I'd like to build 6 regression models (or use multivariable regression) and find out ...
0
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0answers
11 views

VAR Model: Non-stationarity of variables

I am currently working on an empirical analysis in R. To give you some background information: I want to estimate a VAR-model to subsequently develop IRFs from it (using cholesky decomposition). My ...
0
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0answers
5 views

How to measure the terminal conversion rate of a population using Bayesian updating

I have a time-lagged, multi-step conversion funnel. For simplicity, lets assume it looks like this: Lead submit ----> Lead contact ----> Lead convert Where ...
2
votes
0answers
13 views

Interpretation of variance of negative log probability

Given some discrete random variable $X$ with pmf $P(X)$ the expectation of its negative log probability $H(X) = E_{X}[-log(P(X))]$ is defined as the entropy which is an important statistical quantity. ...
0
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1answer
9 views

Invoice Extraction

What topics should I read on to prepare myself for data extraction from invoices (in image file or PDF). Basically I will have a file with invoice and need to extract from it such information as ...
1
vote
1answer
15 views

Calculating variance of MC estimator of an integral

Let $$ f(x) = \sqrt{1-x^2}, \quad I = \int \limits_0^1 f(x) dx. $$ We consider the following estimator of I: $$ \hat{I}_n = \frac{1}{n} \sum \limits_{i=1}^n f(X_i), $$ where $X_1, X_2, ...$ are iid $...
0
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0answers
7 views

Power-Query/R: what is the correct data-format the raw data should be stored in?

I am new to BI and its core programms. As in the past I manually downloaded report-files, clear them out and adjust data I was looking for a way to automate this and heared about Power-Qurey for Excel ...
0
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1answer
6 views

Adjusting for age and gender in ANOVA

I am performing an ANOVA to compare the means of three groups. However, I need to adjust for the effects of age and gender in the ANOVA. I'm not quite sure how to go about it in R. Conventionally, I ...
1
vote
0answers
22 views

ARMA: order selection with LASSO

I'm trying to forecast daily data (I have 15 years of historical data) with complex seasonality: weekly, monthly, annual and also irregular seasonality due to moving events like Easter. As suggested ...
0
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0answers
3 views

MANCOVA - TYPE III

Has anybody an experience with MANCOVA - TYPE 3? I've usually used the function "mancova" (package jmv), but there is not possible to change the settings and the result is always "type 1". Does ...
1
vote
1answer
19 views

Probabillity of a measurement belonging to a certain series

We have done a bunch of measurements of air speed in function of pressure drop for different stack configurations. Stack configurations entail: the number of films in the stack (known) the distance ...
0
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0answers
11 views

What could explain a loss geting very small quickly in a LSTM network?

I am trying my first LSTM with keras to classify time-dependent data sets. I have created a training and a testing data sets, which I have normalized: ...
0
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0answers
10 views

GLMM with ex-Gaussian distribution function (trial-level reaction time data)

I'm trying to use GLMM in R to fit a mixed-effects model (3 categorical predictors, 1 continuous predictor) to trial-level reaction times from a group of participants. The reaction time ...
0
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0answers
5 views

Error while concatenating Keras layers

I am trying to build an LSTM model to predict temperature for a given day using say past 7 days of temperature, rainfall etc of a Zipcode or PinCode. I understand that the training dataset needs to be ...
0
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0answers
9 views

How to determine determinants of absenteeism ? Multivariate + Python (?) [closed]

I hope this message will find you well My main question would be : were to focus ? And for you to be able to answer that, I should give you some informations, both on where I am, and where I'd like ...
0
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0answers
5 views

How to perform bootstrapping to compare CI of mediation analysis in Python

I'd like to perform a mediation analysis in Python and have done the following so far. ...
0
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0answers
3 views

Compare ranges from two GRanges and check if the ranges from the first GRanges is contained in another [closed]

I have the following ranges as GRanges data {Ranges_1}: 1-2, 2-4, 3-6, 6-8, 2-8, 8-11. {Ranges_2} 1-5, 6-10, 11-15, I need a mapping from Ranges_1 to Ranges_2. Something like following (1-2) -> (1-...
1
vote
1answer
22 views

Marginal distribution

A loss distribution has PDF - $f(x) = 1/x^2$, for $x > 1$ An insurer finds that the time in hours it takes to process a loss amount x has a uniform distribution on the interval $(\sqrt x, 2\sqrt x)$...
0
votes
0answers
5 views

Anova test for variable contribution

I wanted to ask about anova F-test. Can this test be used to measure coefficients contribution on dependent variable? Anova test compares variations between and within a certain groups and in linear ...
0
votes
1answer
35 views

QQ-plot indicates normality of residuals but density plot does not

My QQ-plot indicates normality (a fairly straight line), but my density plot shows departures from normality. Why is this happening? Is this a big problem for my model? Here's my model syntax: <...
0
votes
0answers
16 views

Is CV inflated when mean and standard deviation are negatively correlated?

I have two quantitative traits coming from 145 individuals x 12 environments combination. My goal is to correlate the specialization of each individual (trait 1) to the mean of each individual across ...
0
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0answers
13 views

Show that the sum of two random variables is a mixture

Take any $({\lambda},{\mu},F,G)$ such that 1) $\lambda\equiv (\lambda_1,..., \lambda_J)$, $\lambda_j\in (0,1)$ for each $j=1,...,J$ and $\sum_{j=1}^J \lambda_j=1$ 2) $\mu\equiv (\mu_1,..., \mu_J)$ ...
0
votes
0answers
6 views

Interpreting ANCOVA results

I have one continuous independent variable weight and one categorical binary independent variable gender. Gender is a binary column consisting of 0 and 1.From the linear model summary below my ...
0
votes
1answer
24 views

Threshold ROC vs. Cut-Off in confusion matrix (binary regression)

I am trying to understand the link between the threshold in ROC-analysis and the threshold defined in classification table. Criterion is binary with 0 or 1. 1) Someone can determine a confusion ...
0
votes
1answer
7 views

How do the errorbars change when time series is mean subtracted?

I want to subtract the mean from my time series. Each data point has a corresponding errorbar. I calculate the mean by fitting a constant with a MLE estimation and estimate the standard error with the ...
0
votes
0answers
15 views

Comparing between-group change from linear mixed model

I have data for people who participated in a randomised clinical trial. Approximately half received a lifestyle intervention, the others received nothing. Measurements of the ...
0
votes
0answers
4 views

Formatting mixed (within, between, and observed) effects with lme4

I'm new to lme4, so apologies for the simple question. I have the following variables: W: within-subject (categorical: a, b, c, d, e, f, or g) B: between-subject (x or y) age: observed (continuous) ...
2
votes
0answers
19 views

Is $tr(B(B^TWB + D)^{-1}B^TW) = tr((I + D(B^TWB)^{-1})^{-1})$?

I am reading Eilers and Marx (1996) and at the beginning of page 94 they write, for $Q = B^TWB$, $D$ a symmetric positive definite matrix and $W$ a diagonal matrix, \begin{align} tr\left(B(Q + D)^{-1}...
0
votes
0answers
7 views

How to calculate “Rolling Quartile” in a forecast

I have an hourly forecast (let's say it's for rainfall) projected for 40 years. I am using this forecast to plan an activity (for example: outdoor construction; you don't want to plan to be working ...
0
votes
0answers
8 views

Social Network Analysis: assortativity between two classes and network structure

I have a network where nodes are labelled in two classes "a" and "b". I want to measure how connected these two groups are and I looked at assortativity by group. I want to use this measure in more ...
0
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0answers
7 views

PCA Before Random Forest [duplicate]

I am starting to work in data science and machine learning and I have a little question. I am trying to construct a model that predict a continuous variable, it means, a regression model. I have nine ...

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