0
votes
0answers
2 views

“Likelihood Ratio” for multiclass

If i have 2 classes, the likelihood ratio gives me a boundary like the image below. What if i have 3 or more classes ? What test can I use to classify an input data ? What if it is a mixture of ...
0
votes
1answer
3 views

Feature selection vs PCA vs the Intuition?

which one should i choose? how can i combine them (i.e. in series or in parallel)? what if there are dummy features in my data?what if my Intuition missed things up?
0
votes
0answers
6 views

What explanation can i give for having a negative correlation coefficient but positive regression coefficient? [duplicate]

The first table is the regression results showing negative correlation coefficients for all variables. However in the regression table below, only EXR shows the same association as the correlation. ...
0
votes
0answers
4 views

Does shapiro.test use the Rahman-Govidarajulu extension?

I was just by chance confronted with an odd inconsistency. The Wikipedia Page on the Shapiro-Wilk test suggests the original Royston algorithm is maxed out at a sample size of 2,000. ...
1
vote
1answer
6 views

large sample and significance

I have a very large sample (790 million rows), and in this case, even small difference are determined to be significant, p <0.0001. The 95% C.I.s are very sharp. In this case, these tests (t-test, ...
0
votes
1answer
7 views

Is there a concern for multiple comparisons when ranking instead of using significance?

Let's say I have many ANOVA tests on the same data using different factor variables each time. Then, I want to rank the F-statistics for all of those tests. Notice that I'm not interested in ...
0
votes
0answers
4 views

How to determine counts of viruses from limiting dilution assay

My question relates to a common experiment in the field of virology. Let me give some background so you understand why I'm asking this question. When producing virus for an experiment you typically ...
2
votes
0answers
9 views

What is the difference between the Monte Carlo Method in R package 'DMwR' and a normal Monte Carlo Method?

I am trying to estimate the performance of a machine learning model on time series data. I saw the example of model evaluation using Monte Carlo Estimates from the book "Data Mining With R Learning ...
0
votes
0answers
12 views

Using confidence intervals with Simple Linear Regression

So simple linear regression is performed on 3000 data points, and 1000 data points are withheld. How can we use confidence intervals, along with the withheld data points, to assess the predictive ...
0
votes
1answer
7 views

Generalized Hurst Exponent - What value to specify for $\tau_{\max}$?

Consider a time series $X: S \to \mathbb{R}$, where $S := \{\nu, 2\nu, 3\nu, \ldots T\}$, and $T$ is a multiple of $\nu > 0$. For each $\tau \in (0, \tau_{\max}] \cap S$ and $q \in \mathbb{N}$, ...
0
votes
0answers
6 views

how to achieve function criterion to be close to zero [on hold]

I wrote this R script to solve solve this system of nonlinear equations using nleqslv package. ...
0
votes
1answer
4 views

How does DeepMind's DQN agent determines target values for sampled episodes?

In DeepMind's paper titled Human-level control through deep reinforcement learning authors present Algorithm 1 (available in the paper reachable with mentioned link) for training of deep Q-learning ...
1
vote
0answers
3 views

Modelling a Static Bayes Net versus Dynamic Bayes Net

I have a Bayes Net with 20 variables, but I found out that one of the Parent variables is dependent on the previous value of its Child as: C(t-1)->P(t)->C(t) C and P are binary (True or False). All ...
1
vote
1answer
11 views

Finding subset of data where the 'B' in A/B testing is true

Suppose that I have implemented a referral program in my product, in which I offer rewards to a user whenever one of their referrals uses my product. Say, we reward him with gift/prize 'A'. I am also ...
0
votes
0answers
4 views

Standard error for an estimate of invented statistic

I created a statistic that is the division of two proportions. Now, I wanted to compute the standard error, which I know how to calculate for each proportion: $$SE = ...
0
votes
0answers
6 views

Find a significance difference between two models

I am trying to determine if immigration status is a determinant of risk preferences. To do this, I am using the 2014 Health and Retirement Study data which has approximately ~20,000 participants and ...
-2
votes
0answers
12 views

Aggregate with custom function [on hold]

I am new to statistics, I have quick doubt regarding the aggregate custom functions. Could you say what would be the sum(x) and length(x) for each row from the second snap? but am able to understand ...
0
votes
1answer
3 views

Why is my Spearman's Rho result contradicting my Wilcoxon matched pairs?

In brief I'm trying to find out if 62 people perform better on test one or test two. I ran a Spearman's rho and it has come back positive and significant with a moderate strength. I.E As the test 1 ...
0
votes
0answers
8 views

Strange predictions from GAMs

I am fitting a GAM model to data of capture success in trapping sites using the mgcv package in R. The independent variables are proportions of land cover types. Here are: the output of my model: ...
0
votes
0answers
7 views

Partial identification for layman

Can someone please explain Manski approach to partial identification in very basic terms? I have gone through a lot of stuff but failed to find an intuitive explanation. I also don't understand how ...
1
vote
1answer
5 views

Loss function/error measurement for allocation problem

I'm working on a prediction rule for an allocation problem. So, it's data like this: ...
0
votes
0answers
7 views

can I use the cluster membership from cluster analysis (or LCA) for classification

We had a survey of >1500 patients, and we did cluster analysis and also LCA, and grouped these patients into 3 classes. My supervisor wants to develop a algorithm to predict class membership of ...
2
votes
0answers
13 views

Chi square test in a contigency table with sampling zeroes

im trying to estimate if an association exists between two variables in a 7x5 contingency table (the type of prosthesis with the type of complication). The table contains a lot of sampling zeroes and ...
0
votes
0answers
17 views

When do we have that $E[X_{T+1} | X_T] = X_T$?

Given a filtered probability space $(\Omega, \mathscr{F}, \{\mathscr{F}_n\}_{n \in \mathbb{N}}, \mathbb{P})$: Let $X = \{X_n\}_{n \in \mathbb N}$ be a $(\{\mathscr{F}_n\}_{n \in \mathbb{N}}, ...
0
votes
0answers
11 views

seek help on clustering analysis

I have about 79,000 game players' data and we are trying to cluster these players into different classes. But so far we did not get a consistent cluster solution (we used K-means clustering). I ...
0
votes
0answers
22 views

The Second Hearts Problem

Intro: According to the last part of these lecture notes, if we have a standard deck of playing cards and turn cards until the first heart appears, the probability that the next card is a heart is ...
0
votes
1answer
19 views

Is K-Means used the right way?

I have this model where I have a count of a word. Every day I do a count of the word and then calculate a simple ratio for this word by saying: ...
0
votes
0answers
6 views

xtunitroot rho estimation [on hold]

I am performing the following unit root tests on panel data: Levin-Lin-Chu xtunitroot llc y, lags(1) trend demean Augmented Dickey-Fuller xtunitroot fisher y, dfuller lags(1) trend demean Based on ...
0
votes
0answers
4 views

How to create linear model by group and then predictions for each individual group [on hold]

I'm new with R and have used Stata before. I've found solutions in Stata for this problem but can't seem to find an efficient solution in R. First, I need to predict a metric with itself ...
0
votes
0answers
6 views

Confidence interval for function of two independent samples

INTRODUCTION Let $\hat{g}$ be an estimator of a real variable $g$ depending on two variables: $X,Y$ for which I know that if I had a sample: \begin{equation} Z_{(n)} = \left \{ \big( X_1, Y_1 ...
0
votes
0answers
11 views

Cross validated loglikelihood?

This is probably a silly question: I was playing around with penalized package and cvl outputs a cross validated loglikelihood and another measure just called loglikelihood which is suppose to be ...
0
votes
0answers
11 views

Error propagation with correlation

I have two different multidimensional objects in two different conditions, therefore four different vectors of observations: $$V1_{cond1} = v1_{1,1},v1_{1,2},\dots , v1_{1,n}$$ $$V1_{cond2} = ...
0
votes
0answers
4 views

Difficulties fitting a Cox PH model with categorical interactions to complex survey data

I'm attempting to fit a Cox proportional hazards model to a set of NHANES data; the code to load and clean the data is here, and the resulting dataset is here. The difficulty I'm having is ...
0
votes
2answers
12 views

Scaling predictors in ARIMA model

If a predictor in an ARIMA model has much lower magnitude than the variable you are trying to predict, then do you need to multiply it by a scalar in order for it to be an effective predictor in the ...
1
vote
1answer
31 views

AICc is picking overly complex models - something stricter?

I'd like to know if there are "stricter" alternatives to automated model selection than AICc / AIC / BIC. We have approximately ten thousand curves, and for each we'd like to find the most ...
1
vote
0answers
9 views

Interpreting PCA results on gene expression data

I'm working on a gene expression dataset from patients who either have systemic sclerosis or not. I normalized the data with housekeeping gene values and scaled the expression values for each DNA ...
0
votes
0answers
5 views

Normalization of data between 0 and 1, using the ecdf function in MATLAB [on hold]

I would like to normalize/transform data in a variable x such that the new variable y contains values between 0 and 1, computed according to the empirical cumulative distribution function of variable ...
1
vote
0answers
12 views

Number of Exponential Summands in fixed interval is Poisson

What is the most clever way to prove that the number of independent exponential summands in a fixed interval is distributed as a Poisson random variable? I can do it one way, but I would like to know ...
0
votes
0answers
11 views

More than one output neuron firing [on hold]

I am building a neural network to solve a multi-class classification problem. Is it possible for more than one output neuron to fire?
0
votes
0answers
6 views

Understanding output from Survival Analysis(Cox's Regression)

I am using SAS to run Cox's regression.There is a keyword "survival=" which supposedly gives the estimate of survival function. As far as I understand, the survival function is dependent on time and ...
2
votes
0answers
8 views

two samples comparison with cyclic variables

How to check if two samples are from the same distribution, when the variable is cyclic? A simple answer for non-cyclic variable is the Kolmogorov-Smirnov test. What is the equivalent for cyclic ...
0
votes
0answers
5 views

Partial R2 for regression containing both linear and quadratic terms

I’m trying to get an idea of whether age or rate of aggression in my study species explains more of the variance in cortisol level across individuals. I already know that the relationship between age ...
0
votes
0answers
15 views

Why do VAR forecasted values radically change depending on which month historical data end?

I am building a model to forecast housing variables using vector autoregression. I am encountering spurious results. My forecasted values change dramatically depending in which month the historical ...
3
votes
0answers
39 views

Sampling from $f(x)$ given approximation $g(x)$

Suppose you want to draw samples from an (unnormalized) pdf $f(x)$, $x \in \mathbb{R}^d$, $1 \le d \le 20$, which might be expensive to compute, and you have a (normalized) pdf, $g(x)$, which is an ...
0
votes
0answers
10 views

How to inferring the casual relation between two point processes? Edit

I have two point processes. One is the spike time of a neuron and the other is when a rat licks the sugar water. I want to find out if there is any correlation and causation between these two ...
1
vote
1answer
5 views

How to normalize and compare growth rates between variables at different stages of some kind of growth model “curve”?

I have a data frame that has various capital and metropolitan cities with various economic, market and performance data. One set of variables is each total annual non-domestic visitor volume and the ...
0
votes
1answer
25 views

Learning from clicks on Ads [on hold]

I need to build an algorithm that predicts the number of clicks a facebook ad would get in the next 7 days. Based on the given requirements, I prepared a dataset consisting of the following ...
0
votes
0answers
13 views

Achieve multiple random effects and interactions with lme4 in R

I am trying to replicate a mixed effect analysis where the authors claim that they used the following scheme: Fixed effects treatment, year of observation Random effects block, interaction ...
0
votes
0answers
15 views

How to plot a vglm/propodds regression in R

Hi I'd like some help plotting the following regression in "r": fit1_usesrp <-vglm(rp ~ is.native + is.male + oh + cjs + age2 + tw ,propodds, data = dummydata ...
0
votes
0answers
7 views

Non-linear least square minimization using for three-dimensional data [on hold]

I have a 3D data and I would like to fit a non-linear model to the data using lmfit. This is the code I have written but it doesn't work. ...

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