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2 views

Weights in cluster analysis in R

I have a data set of responses to a survey administered in three different locations. The number of responses from each of these, however, do not represent the underlying population of each area. I ...
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0answers
4 views

Most likely domain element in probabalistic forward model

Suppose I have some probablistic forward model $m: T \rightarrow U$, and that the model is then conditioned on observations $u_1, \dots, u_N$ from U. [More specifically, by 'probabalistic model' here,...
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0answers
3 views

Repeated-measure contingency table with two variables with many levels

I am trying to analyze the results of a survey on what would make people of different ages visit certain tourist places. However, age was collected as age-group (not my fault). Hence, it is a ...
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0answers
17 views

Consider tossing a coin 2 times, there are 4 possible sequences of outcomes, what is the name of each sequence, in the context of stochastic process?

In probability theory and related fields, a stochastic process is a mathematical object usually defined as a family of random variables. In probability and statistics, a Bernoulli process (named ...
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1answer
7 views

What is the difference between data perturbation and differential privacy?

I cannot distinguish the terms "data perturbation" and "differential privacy". If the data perturbation is the process that adds some small value sampled from specific distributions such as Laplacian ...
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0answers
6 views

How can I smooth data in 2D coordinates that has time-dependent error?

I have collected some GPS data from running over and around a hill many, many times. The hill itself is about 9-10 meters high compared to the ground around it, although when I collected data, my ...
1
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1answer
11 views

What is the relation between “conjugate priors” and the approximate inference?

I know that "conjugate prior" is to help us calculate the the denominator of the Bayes formula(to make the calculations easier). And I just learnt to approximate the inference by mean field ...
2
votes
1answer
30 views

Expectation of two $X \sim N(0, \sigma^2)$ $Y \sim N(0, \sigma^2)$

IF ` $X \sim N(0, \sigma^2)$ $Y \sim N(0, \sigma^2)$ ` X and Y are independent => $X^2 \sim Gamma (\left(\frac{1}{2}\right), 2\sigma^2)$ $Y^2 \sim N(\left(\frac{1}{2}\right), 2\sigma^2)$ ...
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1answer
3 views

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 ...
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0answers
10 views

3 way ANOVA, residuals not normally distributed

It has been a while since I have learnt about more complex stats and I am utterly stuck, not even sure I am using the right test at this point. I am trying to perform a 3 way analysis of variance ...
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0answers
10 views

Figuring out GLMM family for S-shaped curve, or going non parametric?

I have two processes that output n-square matrices. I am interest in modelling these matrix norms as a dependent variable, according to the process used, and the matrix size n as predictors. I ...
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0answers
12 views

How to show an alternate data processing inequality concerning KL divergence between conditionals?

Suppose $(Y,X) \sim F \in \mathcal{P(\mathbb{R^d})}$. Consider an arbitrary transformation $f$ that acts on $X$. My intuition is that the following should be a result in information theory: $$ \...
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0answers
4 views

Intensity normalization with segmented ROI on black background

I have a set of segmented ROIs .jpgs against a black background. Pixels in the ROI range from 0 to 255 in grayscale (1 channel only). I want to normalize these intensities in order to feed it into a ...
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0answers
19 views

Posterior predictive

The posterior predictive distribution is always defined by the densities. Assume $X_1,X_2,...$ are conditionally i.i.d. given $\mu$ according to measure $P_\mu$, where $\mu\sim Q$. Let $\mu\mid X_1,\...
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0answers
22 views

what is a parameter and hyperprameter [duplicate]

I hear in many articles the word parameters and hyperparameters but I don't know what they mean by that. Are they variable or the weights of the nodes? explain me in an intuitive way as an analogy ...
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0answers
15 views

apply function function with 2 arguments, 1 a vector constant [on hold]

I am writing only after many hours of futile experimentation. I read in the data, ...
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0answers
10 views

When can we use fixed design regression results for the random design setting?

Suppose I have an independent vector $X$ and a dependent scalar random variable $Y$ and I wish to construct a regression model to predict $Y$ using $X$ given data $\{(x_i,y_i)\}_{i=1}^{n}$. For ...
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0answers
19 views

predicting who will buy what [on hold]

what machine learning algorithm would be most suitable to predict which customer will buy what and when they will buy it ( consider historical data is available). I have tried : predicted next ...
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0answers
3 views

Comparing empirical and theoretical estimates of the number of right-censored values

Suppose I have right-censored data, so that observations are still present but are top-coded. In my case this is income data for, let’s say, individual people, and associated & probability weights....
2
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0answers
12 views

The extrapolation problem: model selection, performance metrics, and improvement

Machine learning models are fit to a response within a given range. This leads to weak and sometimes disastrous performance when it comes to instances outside that range. When the underlying mechanism ...
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0answers
4 views

what is the cost function for a perceptron muticap

I have the function of cost or error of a perceptron of an entry and exit ...
0
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1answer
21 views

R-squared and sample size

I was wondering if R-squared is affected by the sample size? Is adjusted R-squared also affected? The reason behind this though is, that i have run a multiple linear regression on two samples. The R^...
1
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1answer
15 views

comparing proportions of several groups

I have data of existence of a feature in n samples represents m groups. I want to find features with significantly different proportion in a group. I was thinking about the followings, and will be ...
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2answers
31 views

two-sample t-test with unequal variances

As part of my homework, I've got this question. Can someone confirm whether this statement is true or false? To help me understand I would prefer if an explanation is also given. "The two-sample t-...
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0answers
8 views

Computing the means of the values between pairs of quantiles, and its variance

I have a set of observations drawn from a complex survey sample including income data for each person. Using, e.g., R’s survey package, I can estimate the quantiles and also an appropriate variance ...
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0answers
6 views

How do I identify curves in a series with multiple groups?

I have a scatter plot which seems to suggest some patterns in the data. For example there seems to be a sin wave continuing from the orange series. If the orange points are in fact the beginning of ...
0
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0answers
18 views

What are assumptions of generalized linear model?

can anyone help me and tell me what I have to check to conduct the generalized linear model in SPSS. (What are assumptions of generalized linear model?). thank you so much for any try to help.
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0answers
7 views

Formula for type III sum of squares of the intercept term in linear multiple regression

assume we have the regression model: $$Y = b_0 + b_1 x_1 + \dots + b_k x_k + \varepsilon $$ I know the formulas for all type III sum of squares for the regression terms except the formula for SS of ...
0
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0answers
9 views

Missing values in large spatial data

I have a groundwater dataset (4000 locations). For this data, the depth is very important to coordinate the data. I found that there are about 415 missing values in ...
0
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0answers
12 views

Problem on quadratic form [migrated]

Show that $\{x : x^{T}Ax \le 1\}$ is bounded if $A$ is positive definite, where $x^T=[x_1,x_2,...,x_n]$ and $A$ is an $n\times n$ matrix.
1
vote
1answer
21 views

Detrending time series for regression

I want to perform a regression between 3 variables [x1,x2,x3] that have no trend and no seasonality across their time observations and a variable [Y] that has trend and seasonality. For [Y] I've ...
0
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0answers
16 views

Keras predict probability too high

I've followed this tutorial to create a simple neural network that matches intents. The results are good and the process is relatively fast, however there's an issue with it. The probability is ...
2
votes
0answers
26 views

Ratio = 1 or Difference = 0

In two-sample testing, a standard way of examining for differences in variance is testing a null hypothesis that the ratio of two variances is 1. Let's set up the problem. Why not test that the ...
1
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0answers
16 views

One sample t-Test for proportional data

I have 4 group of fish (n=28 per group). I have measured the amount of time that a fish in each group spent exploring two different objects (A and B) in a squared shape tank. Then I have calculated ...
0
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1answer
8 views

Calculation of critical values

Are the critical values for the two-sample t-test with unequal variances calculated the same as for the two-sample z-test?
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0answers
3 views

Using ezANOVA or ezMixed

I am fairly new to R and have looked into other answers found on SE and SO but still do not feel that my case matches other posters' data. I would like to perform a Repeated Measures-ANCOVA on the ...
0
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0answers
6 views

How should I interpret irregular lag correlation in time series?

I'm not sure how to interpret the autocorrelation pattern I'm seeing in this time series and any help would be very appreciated. Below is the ACF plot for my data. To me this looks like seasonal ...
0
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1answer
16 views

How to represent gender or any non numerical data for a Logistic regression classifier?

I've coded a logistic regression classifier trained on the Kaggle Titanic dataset to predict whether or not a passenger will survive. I've noticed that depending on how I represent the gender the ...
-1
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0answers
11 views

How to retrieve the data frame used in a GEE model fit? [migrated]

I have a longitudinal data frame with multiple rows per id. ...
-1
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1answer
37 views

Which is the correct method for outlier analysis on a dataset for modelling?

I'm trying to build a regression model but my data-set have many outliers points which I need to analyze and then remove them. There are two ways to do it, 1) First do all the analysis on every ...
0
votes
1answer
14 views

How can I adress problems of heteroscedasticity in mixed model analysis?

I am analizing pupil size data using mixed model analysis in R. I use lme() from package nlme. However, I am encountering serious problems of heteroscedasticity and ...
0
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0answers
5 views

Variance Components of a Random-Intercept Covariance Matrix

My professor wants me to explain how the parameters of my model are estimated via penalized quasi likelihood. However, my understanding of (generalized linear) mixed models is still very basic and ...
0
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0answers
4 views

Path Model with (endogenous) Treatment - which model?

I have collected data on the intention to create a new business of my students. I measured it before the course (t1) and after it (t2). I have data on their absenteeism in class and the time they ...
0
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0answers
15 views

Estimate the time series like an event was never happened

I have data from a website where a specific advertising campaign happened a couple of years ago. What I want to do is to estimate how the signups on that website would have been without that big ...
0
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0answers
8 views

Simulated returns from copulas to use in portfolio allocation

I am currently trying to do some portfolio optimization by reproducing the methodology found in Sahamkhadam, Stephan & Östermark (2018) ("Portfolio optimization based on GARCH-EVT-Copula ...
0
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0answers
5 views

Is there a way to assess how much and in which direction a predictor is associated with class in my classifier?

I searched the forum, and couldn't find a matching question. I am building an MLP to predict an outcome (occurrence of a medical condition) in Weka. Previously I identified positive and negative ...
0
votes
1answer
13 views

What does $w_{ni}$ mean in the weighted nearest neighbour classifier?

Wiki gives this definition of KNN In pattern recognition, the k-nearest neighbors algorithm (k-NN) is a non-parametric method used for classification and regression. In both cases, the input ...
0
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0answers
12 views

How a softmax function can be used in multiclass classification?

I'm trying to understand how a softmax function help classify in multi-class classification. In Andrew Ng video, he shows how a simple 1 layer neural network, with 2 inputs ($x_1, x_2$) and 3 outputs ...
0
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0answers
9 views

ARIMA(0, 1, 0) or ARIMA(0, 0, 0) for Stock log-Returns Forecast

I'm trying to forecast the log-returns of Amazon's stocks using the ARIMA model, so I went through the traditional procedure of examining the autocorrelation plot and the partial autocorrelation plot ...
4
votes
2answers
174 views

Regression when x and y each have uncertainties

I have a set of $N$ points $(x_i,y_i)$. $X$ and $Y$ both have some noise associated with them due to measurement inaccuracy however the relationship of the underlying true values (i.e. if we could ...

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