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22 views

How do you apply random forest classification, not regression? Keep getting error even though my response variable has been converted to a factor [closed]

I keep getting the error message " Warning messages: 1: In train.default(x, y, weights = w, ...) : You are trying to do regression and your outcome only has two possible values Are you trying to ...
0
votes
1answer
16 views

Can I compared the output probability of two machine learning models?

I'm sorry if this is a silly question. Suppose there are two logistic regression models $M_1$ and $M_2$ trained on the same (or similar) dataset, and their outputs of given input $x$ are $P_{M_1}(y \...
0
votes
0answers
5 views

Performing a MWD test in R

0 Hei, I would like to do a MWD test on a model to determine which one is best between a lin lin and a log lin to describe a model. I found than in R one can use the PE test from lmtest, but I find it ...
0
votes
0answers
18 views

Joint densities do not exist, compute probability

I am taking a course in probability and in one of the PS I have got the following description: $Y_i \sim \exp(\lambda_i)$ for $i=1,...,n+1$. Define $X_i = \min(Y_i,Y_{n+1})$. In the first subsection ...
1
vote
1answer
184 views

Set a threshold for a sequence

I am now having a sequence of numbers, e.g. $x_1, x_2,\dots , x_N$, ($0\leq x_i\leq 1$), which may represent the correlation between a couple of measurements. I want to set a threshold for this ...
1
vote
0answers
11 views

What are the properties of the distribution of medians from samples of a set of integers?

Given a set of integers $S = \{1, 2, 3, ..., n\}$ I draw uniformly at random without repetition $m$ integers a large number of times ($1 \leq m \leq n$). For each of these samples (each of size $m$) I ...
2
votes
2answers
17 views

Confidence interval given the population mean and standard deviation

Say we have a normal distribution with mean 10 and standard deviation 5. How do I get a two sided and one sided (left/right) 90% confidence interval using this? This is the actual question I am trying ...
0
votes
0answers
6 views

the density function [closed]

Two random variables $X$ and $Y$ have the density function $$ p_{X Y}(x, y)=\left\{\begin{array}{cc} C(y-x+1), & 0 \leq y \leq x \leq 1 \\ 0, & \text { elsewhere } \end{array}\right. $$ where ...
0
votes
1answer
698 views

Ordinal Logistic Regression with Polr: Compare multiple treatments

Let's say I have information about three stages of cancer (Stage 1, Stage 2, Stage 3) and three treatment groups. Now I'd like to compare if the odds ratio for all of these three groups are different. ...
0
votes
0answers
8 views

Log-transformation of parameters in MLE

I am building a negative log likelihood function in R and I have transformed the parameters both in the optimizer (MLE2) and in the function. Below is the negative log likelihood function: ...
0
votes
1answer
11 views

Calculating variance between groups in ANOVA

I am extremely confused about getting the between group variance component from an ANOVA. To my understanding, variance within groups ($V_w$) equals the mean of squares within groups ($MSW$) and the ...
1
vote
1answer
10 views

Is best model selection by RSS equivalent to best model selection by R2 value?

I am trying to compare models using K-Fold-CV using the regsubsets function in R. By default, it states that the ideal model is determined by the $RSS$. I wished to ...
0
votes
0answers
11 views

Which is the best online data science specialisation course? [closed]

I want to switch my career from Marketing to data scientist and I'm looking for the best institute. Also, I would want to know if switching the career is a better option or not?
0
votes
0answers
15 views

What kind of Monte Carlo fits this function?

I want to construct a simulation for the following equation: $\mathbb{E} \left[\max(Z(T),E[Z(T+1)|F_T]) \right]$ Whereby $Z(T)$ is a function of a financial contract consisting of several input and ...
0
votes
2answers
412 views

Is there a Bayesian Non-Parametric one-way ANOVA?

The rough idea is that I am trying to compare linguistic properties (e.g. readability) between pieces of texts from two authors essentially. For this, I thought using an ANOVA would be appropriate. ...
1
vote
0answers
16 views

Distribution of $\frac{Z_1^2 + Z_2^2}{Z_1+Z_2}$ where $Z_1, Z_2$ are standard normals

Let $Z_1, Z_2 \sim \mathcal{N}(0,1)$ be i.i.d random variables. I wish to find the distribution of \begin{align} \frac{Z_1^2 + Z_2^2}{Z_1+Z_2} \,. \end{align} It is well known that $W = Z_1^2 + Z_2^2 ...
1
vote
1answer
52 views

Why is the lower bound of the confidence interval of a model's error relatively constant compared to the upper bound? [closed]

I am interested in studying the effect of increasing data samples for a regression model on train error and test error. For this I have used 95% confidence intervals for different values of a sample ...
8
votes
4answers
1k views

Boosting using other "weak learners" than trees

Descriptions of boosting (and specific techniques like gradient boosting) typically talk about "weak learners" in general, and then immediately switch to discussing boosted trees specifically. Why is ...
0
votes
0answers
16 views

Linear mixed models natural splines plotting regression

Eventually I want to use joint modeling. For this, I need to fit a linear mixed model on the biomarker trajectory, with a random slope and intercept for study ID. I want to use natural splines with ...
0
votes
1answer
29 views

Clustering Standard Errors for Panel Data with multiple groupings

I have a Group-Firm-Year panel data set (i.e., multiple firms make up a group). Suppose I have exogenous variation at the group level over time. In a panel regression with firm and time fixed effects ...
0
votes
0answers
2 views

Can I Use the loo function to help me choose between a Poisson and Bernouilli distribution in bayesian

I have two models exactly similar, but I’m using a Poisson distribution for one and a Bernoulli distribution for the other. Can I trust the information coming out of loo to help me choose? The ...
6
votes
1answer
1k views

Equivalence test for binominal data

I want to apply an equivalence test on my sample to infer whether they are equivalent or not. Since my data are bionominal [0,1] I don’t know whether the TOST procedure (tost() in R) can handle my ...
0
votes
1answer
10 views

Meta-analyzing incidence (count) data with many zero cells

I am conducting a meta-analysis on the incidence of a rare event. I have 15 single-arm studies with events occurring in only 2 studies. The metarate function in the meta package allows for meta-...
4
votes
1answer
357 views

Up to what number of distinct values should I transform a categorical variable in a dummy variable?

When working with categorical variables, it's common to do some sort of transformation. Usually people apply a one-hot encoding. Putting it simply, we transform a categorical into a dummy variable. ...
1
vote
0answers
83 views

Expected value of the parameters in linear regression (trying to understand which part is constant and which isn't and why)

I'm studying Linear Regression and trying to proof/demonstrate some properties of the parameters. When I started working with the expected value of the slope, I got confused with something. I actually ...
-1
votes
0answers
7 views

Max number of vote per person [closed]

Population = 75 4 cnadidatets for election Each voter may choose to cast 1 2 3 or 4 votes. Max 1 voter per candidate. What is the max possible # & % of vote per candidate ?
1
vote
1answer
247 views

objective function oscillating in learning for h2o deep net

I'm using the R h2o package for building a deep net with three hidden layers. When inspecting the model object, I'm noticing the training RMSE fluctuates as a function of number of epochs. I'm ...
0
votes
0answers
3 views

Compare regression coefficients across two (or more) svyglm() models

The question I have is related to this one, but slightly more specific. Suppose I use data from a large-scale educational assessment to investigate how students' proficiency in math depends on their ...
0
votes
0answers
8 views

Solving Linear Regression numerically by optimizing Likelihood of errors ~ N(0, sigma^2). What value to use for sigma?

I can solve a linear regression numerically by finding the beta that maximizes the log-likelihood of the residuals distributed N(0,sigma^2). I can do this in Excel using Solver and any reasonable ...
0
votes
0answers
9 views

Applying ranking weights to quantitative mixed-method data?

I have a dataset where some participants were timed doing a task 5 different times with 6 different devices. I want to run a mixed methods ANOVA to find out the mean time differences between the 6 ...
0
votes
1answer
5 views

What is meant by relative frequency in calibration curves

After reading docs on scikit learn on the probability calibration there's couple concerns that bug me. I don’t really understand how the curve values are calculated (y-axis) namely the frequencies. ...
0
votes
0answers
5 views

Unsupervised anomaly detection and classification with event (log) data

I am trying to detect anomalies in a large set of user log events, where most users would be considered “good” and a small minority would be considered “bad.” There are hundreds of event types, which ...
0
votes
1answer
2k views

SVC doing great on validation & test data but scored very low on predicted data

First of all, this is my first machine learning project after taking Andrew Ng's course, so please bear with me. I'm working on the most famous dataset, the Titanic data. First, I split the dataset ...
0
votes
0answers
9 views

Ridge regression - prove derivate is zero at Q* [closed]

How to I prove that the optimal point in L2 ridge regression will make the derivative 0? It's kind of reverse work( I've substituted the q* value in the gradient but not able to prove its 0. L(Q) = 1/...
1
vote
0answers
16 views

Conventions for pmf/pdf

The way I usually see the conventions: for a continuous random variable $X$, the pdf is denoted $f_{X}(x)$ or $f(x)$,where $x$ is an instance of $X$. And for a discrete random variable $X$, the pmf ...
0
votes
0answers
4 views

Evaluating recommender system implicit vs explicit

I have rating data that allows me to create a recommender system based on these explicit rankings. Moreover, I want to test some methods that utilize implicit feedback. I can obtain it by binarizing ...
3
votes
0answers
22 views

Photo attractiveness rating experiment: significance and effect size

I'm a photographer working on a personal project where I experimentally test dating photo advice. I take photos of people under different conditions, changing one variable while keeping others ...
0
votes
1answer
9 views

ANOVA post-hoc correction question

I am currently analysing data from a recent experiment, in which I will perform a 2 way repeated measures ANOVA (exercise intensity [3 intensities] x time [5 time points]). I have a significant ...
2
votes
1answer
703 views

How to evaluate a histogram?

Let's say I have the histogram above which reports performances of some neural networks. The y axis is the bin size, while the x axis is the error, so low errors = high performance. Out of these 15 ...
8
votes
1answer
1k views

Writing PCA as a special kind of auto-encoder

I would like to know if it's possible to view PCA as a particular type of neural network, however, there's one major stumbling block that I haven't yet been able to get past. Define the following "...
0
votes
0answers
9 views

Oracle inequality for LASSO

In chapter 6 of Statistics for High Dimensional Data (Peter BühlmannSara van de Geer), they focus on the normal linear regression model with fixed regressors and begin by stating OLS achieves a risk $\...
0
votes
0answers
12 views

Measuring cumulative number of events in a day

A certain type of event happens in continuous time throughout the day. During some periods of the day (say between 9 am and 5 pm) the event happens more frequently than outside of these times. Given ...
1
vote
0answers
63 views

Hypothesis testing with one tailed test

I have a model: $$Y=\beta_0+\beta_1x_1+\beta_2x_2+\beta_3X_3+\beta_4x_4$$ and I want to test these two hypotheses: $$H_0: \beta_1>-3 \qquad H_a: \beta_1<-3$$ So if I conduct a one-sided test at ...
0
votes
0answers
17 views

dependence of percentage error on size of train dataset with using of bootstrap

I am interested in the problem of the dependence of the percentage error on the size of train dataset in regression problem, where linear regression model is used and my dataset consists of 2 columns –...
3
votes
1answer
2k views

Jeffries Matusita distance for 14 variables

I wish to perform Jeffries-Matusita distance on 14 spectral bands. Is there anyone who can help with how it is done in R?
0
votes
1answer
15 views

The motivation of the value function of the generative adversarial network

The seminal paper on the generative adversarial network, proposes to $$\min_G\max_D V(D,G)$$ where the value function $$V(D,G):=\int p_{\text{data}}(x)\ln p(D=\text{data}|x)\,dx+\int p_{\text{gen}}(x)\...
3
votes
1answer
81 views

Uniformly sample pieces of a rectangle

Say I have a rectangle $R: \left[{0,W}\right] \times \left[{0,H}\right]$ where $W$ is the width and $H$ is the height, with coordinates $\left(x, y\right) \in \mathbb{R}^2$. I would like to randomly ...
0
votes
0answers
9 views

Rationale for the objective function in a flow network based generative model by Yoshua Bengio?

I am reading the Yoshua Bengio et al, Flow Network based Generative Models for Non-Iterative Diverse Candidate Generation. It seems to me the objective of the paper is to generate the flow $F$ given ...
2
votes
3answers
72 views

Simulation in R to check graphically that marginal distributions are correct

The distribution on $R^2$ with joint density $h$ with respect to the Lebesgue measure is: $$h(x,y)=\frac{3}{2}y 1_{A}(x,y), \ \ A=\{(x,y) \in R^2|0<y, x^2+y^2<1\}.$$ Then I have found the ...
0
votes
0answers
20 views

Is this loss function convex?

I am working on a small project to understand gradient descent. I am trying to model noisy cubic data with the ideal cubic polynomial. I am using linear regression with the least-squares method with ...

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