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8 views

is a SVM model non non-reasonable if we don't have soft margin on it?

do all svm models have soft margin? how about if I don't put it in my model? from academic point of view , is it so unexeptable? I don't want to put epsilon on my constraints because I want to solve ...
1
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0answers
39 views

Why do the non-informative a priori distributions give better results than the frequentist estimate?

For example, in the specific case of Markov-Switching GARCH models why is a non-informative prior distribution chosen for GARCH models with Bayesian estimation and why is this approach better than the ...
3
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0answers
20 views

Is explained variance a valid measure for weighted regression?

How should we calculate the R^2 statistics in weighted linear regression? Should we also weight each residual to decrease the sum of squares of the residuals? If ...
2
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0answers
14 views

Statistical Significance in Table Ones

I have a question about statistical and clinical significance. In a non-clinical trials setting (e.g. observational), if the sample size is large for both groups (assume 2 groups for simplicity) ...
0
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0answers
3 views

Incorporating single value with associated standard error into test (N unknown)

I am estimating an evolutionary metric for various genes. Each estimate has an associated standard error. Typically, I'll have a set of genes for which I want to compare its mean to the mean of the ...
0
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1answer
28 views

I cannot decide which test to use for my experimental design - 2-Way ANOVA?

My experimental design consists of 6 treatments, each of which are measured Before and After a particular application. I want to see if there is any difference between treatments both Before and After ...
2
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0answers
12 views

What model to use to evaluate whether the “variability” of one variable is determined by the “variability” of other variables?

I have observations taken for four subjects at a number of points/locations. The data is formatted similarly to as below: I am not directly interested in the impact that a predictor has on the ...
0
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0answers
20 views

How do I determine goodness of fit for a test of n binary decisions?

Let's say I have $n$ pairs of items. For each pair I select one item over another due to some perceived trait. This could be anything, for example, identifying which image is brighter than the other ...
1
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0answers
11 views

Computing the error function defined over a transformed dataset

I am currently reading chapter 5 from Christopher Bishop's Pattern Recognition and Machine Learning book. Having an infinte dataset $\{({\bf x}, t)\}$, and an estimated value $y({\bf x})$, I am ...
0
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0answers
15 views

Discrepancies in p-values between t.test vs regression after random forest analysis [duplicate]

I was trying to analyze two groups of samples for multiple variables. I first used Boruta (random forest analysis) test to determine the importance of variables in my data. ...
1
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1answer
7 views

Parallel multi-task learning vs. continual learning

Assuming we want to learn k tasks jointly, and the data for all tasks are available. We may either train a model with parallel multi-task learning (eg. each batch is a mixture of samples from the k ...
0
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0answers
2 views

How to do model fit if the Hosmer Lemeshow GOF is less than 0.05

I have a data set that the response variable is count data, with other predictive variables all categorical. I used the stepwise logistic regression to try to find the best model fit. I used the code ...
1
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0answers
71 views

Loss functions for Regression task

I am trying to understand the idea of Loss functions For Regression Task perfectly. I have read many textbooks and articles, and I came up with questions related to this subject. Several different ...
1
vote
1answer
17 views

Unconditional mean of ARMA(2,1)

Why is the unconditional mean of this model equal to 0? Can we tell if we don’t know anything about stationarity? I’m self studying and this got me confused. Thank you in advance.
0
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0answers
18 views

Combination of categorical/binary variables vs an ordinal variable [on hold]

I am conducting an analysis for my dissertation on the topic of how usage of technologies is connected to motivation in sport. My data contains respondent ID, age, gender, a number of answers on a ...
0
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0answers
9 views

Matching subjects with themselves when evaluating short term outcomes

I am considering a simple causal inference scenario; Let's say we want to examine the effect of paracetamol (treatment) on curing headache (outcome). When performing matching, is it okay to match ...
0
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0answers
9 views

R code to estimate the Survival function for interval censored and left truncated data [on hold]

I have interval censored data with some late-entry subjects. Does the Icens package in R take into account left truncation to estimate the Survival function and if so how? Alternatively, is there an R ...
0
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0answers
17 views

Calculating the AIC/BIC from modelled steady state distributions

Usually, the $AIC$ or $BIC$ (Akaike/Bayesian Information Criterion) are calculated based on modelled and observed random variables. Does it make sense to instead calculate the $AIC$ or $BIC$ from ...
2
votes
1answer
38 views

Metropolis Hastings proposal for one parameter restricted to less than the other

Suppose I have parameters $\theta_0$ and $\theta_1$ with prior $$ p(\theta_0,\theta_1)=p(\theta_0|\theta_0<\theta_1)p(\theta_1),$$ that is, $\theta_0$ is less than $\theta_1$. The distributions ...
0
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0answers
7 views

Twoway fixed effects with pglm (and plm) package

I'm trying to estimate a poisson model with location and time fixed effects using the pglm package in R but noticed that including the time index has no effect on the output and seems to be ignored by ...
1
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1answer
31 views

Do i need independence for paired t-test?

I am testing the mean change in IOP of eyes in a glaucoma study. When looking at just the 'Primary Eye', i am using a paired t-test to test the mean change from baseline as this is one eye per patient....
0
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0answers
11 views

How would phi of the gaussian rbf kernel map a 100-by-3 dimensional feature matrix?

Would a 100-by-3 dimensional feature matrix be mapped into a 100 dimensional or into a infinite dimensional feature space, if the mapping would not be bypassed by the Gaussian RBF Kernel? Following ...
1
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2answers
20 views

How do I forecast quarterly public expenses based on annual budgets and potentially other variables?

I have some time series data from 2008 and forward (see below) on quarterly public expenses and annual public budgets. I would like to forecast the last two quarters of 2018 as precisely as possible, ...
1
vote
1answer
35 views

Regression terminology, predictor vs IV vs?

A reviewer has objected to our use of the term "predictor" in a multiple regression analysis using observational data. They argue that because the model is intended to be explanatory and not ...
3
votes
1answer
37 views

Motivations for experiment design in statistical learning?

My interests in statistics centre around statistical learning, including Bayesian inference, inference in combinatorial spaces, Monte Carlo methods, Markov decision processes, modeling stochastic ...
0
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0answers
26 views

is this sampling from a simplex?

Simply, if I sample $n$ $X_i$s from an exponential distirbution; that is $$ X_i \sim exp(1) $$ Then prove that the vector $$ \left ( \frac{X_1}{\sum X_i}, \frac{X_2}{\sum X_i}, \cdots, \frac{X_n}{\...
0
votes
1answer
18 views

Extremely High T-Test P-Value but Extremely Low F-Test P-Value

So I'm running a logistic regression on a binomial variable in R and came out with the following model. ...
1
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0answers
11 views

Confidence interval of amplitude and horizontal shift

I have a linear model with sine and cosine wave as predictor. Y~$\alpha$sine(...)+$\beta$cosine(...). From the parameter estimation, I know the estimation of the coefficients are: $\hat\alpha$ = 0.65(...
0
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0answers
28 views

Precision, Recall, F1 Score and multiclass confusion matrix

My goal is to evaluate some clustering algorithms. Lets say that I’ve got one set o elements: { 1 ; 2; 3; 4; 5; 6; 7; 8 }. This set was grouped by human into two groups: (1 ; 2; 3; 4; 5; 6; 8) and (7)....
1
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0answers
10 views

Changing lattice coplot strip font [migrated]

I'm trying to change the size of the strip text for biom and days. I saw other posts suggesting to use ...
0
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0answers
10 views

Machine Learning Pipeline and remove weak correlated variables [on hold]

I am very new to machine learning and I am trying to understand the whole process of preparing the data for the machine learning part. I am making use of pipeline from sklearn. Lets say I have the ...
0
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0answers
9 views

Mix pdf and cdf in binary response model [duplicate]

Let's suppose that I have a model that tells me how likely is for an event to have come after a certain time lapsed, given by some kind an exponential distribution, i.e. $$ \mathbb{P}(T_E < t) = \...
1
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1answer
17 views

Two-way repeated measures ANOVA with two independent variables: possible? Good idea?

I have one DV: performance on research knowledge test (pretest and postest, so repeated measures--interval level measurement). I have two IV: 1) Online textbook or traditional textbook and 2) Onsite ...
0
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0answers
22 views

Difference between PCA and Mahalanobis? [on hold]

PCA uses the directions of the data with the highest variance and omits those with lower. Next, it constructs a new space with the eigenvectors of these directions. Mahalanobis uses the covariances ...
-1
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0answers
6 views

Multiple orthogonal regression (aka multiple total least square) in excel [on hold]

I am trying to make a multiple orthogonal regression in excel. I need to do it strictly in excel - cannot use programming languages. I did not find any free addins that calculate it for me, ...
1
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0answers
23 views

Temperature timeseries agreement significance test

I hope my question wasn't answered before, but after extensive research I wasn't able to find something similar, so I'm asking for help (this is not my field). I have air temperatures timeseries ...
0
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0answers
6 views

Equivalent of nested design for crossed factord

I want to run the equivalent of a nested design except my factor are all crossed, so it is like a repeated measures anova but I have more than one factor repeated within the other. My factors are : ...
0
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0answers
10 views

Law of Total Expectation Estimation With Countably Infinite Support

I am attempting to estimate $E[W] = E[E[W | A]] = \sum E[W | a] \Pr (a)$. I have expressions for both the conditional expectation and the probability of a, where the probability is Poisson distributed ...
0
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0answers
17 views

Interpreting interaction effects in Factorial design

I have factor1 with 2 levels fully crossed with factor2 (5 levels). Now samples are collected from same experimental units at 6 different times. Time is used as within-subject variable. When I run ...
0
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0answers
12 views

How to estimate policy impact using interrupted time series, when outcome variable is a moving average?

Suppose you want to evaluate the impact of a recently implemented policy using interrupted time series because you have no comparison group and the policy was implemented all at once on the ...
0
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0answers
6 views

Cross-classified multilevel model with lagged dependent variable Using R

I am a bit stuck with my model and I wonder if this is even possible using R. Basically I want to use a lagged dependent variable (LDV) in a cross-classified multilevel model (MLM). Following remarks ...
1
vote
1answer
37 views

Combining multiple predictions with Bayes Theorem

I have multiple weather forecasters who each use their own unique, independent calculation for prediction of the weather for the next day. We are only concerned with rain predictions to know if we may ...
0
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0answers
24 views

When to use stratified split and when to use simple sklearn split or hashing based split [on hold]

When to use stratified split in sklearn for splitting the data into test and training set I have California housing dataset and i am splitting income feature. And i am getting more accurate results ...
0
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0answers
24 views

Adjust for confounder in calculating explained variability in cox-regression

My question is closely related to this one. I am interested in the proportion of variability which is explained by a certain covariate X in a cox-model. So I have the cox-model “outcome ~ X”, for ...
3
votes
1answer
66 views

What may be an inefficient estimator of the population mean?

If the sample mean is an efficient estimator of the population mean, what may be an example of an inefficient such estimator?
0
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0answers
16 views

how to create features from datasets with date columns [on hold]

I'm working on a project to score my leads and customers based on the meeting our sales guys do with them. These are the fields- customer_id date (date when visit is completed) schedule_status (date ...
1
vote
1answer
31 views

Creation of contigency table and calculation of effect size (Chi2, Cramer's V)

I am a bit unsure in my approach of applying the Chi2 GOF test to my data and calculating the correct effect size. The situation: I am studying the occurrence of specific biological phenomena in ...
0
votes
1answer
16 views

Calculate Cohen's d for pairwise tukey tests in a 1-way ANOVA

I have the following dilemma: Design: 1 (Group: Patient vs. Control_1 vs. Control_2) between-factors design arrayed as a 1-way ANOVA Analysis: Following a main effect of group perform I perform all ...
0
votes
1answer
15 views

Provide a perceptron learning procedure from the initial separating line linearly separating the classes [on hold]

I try to understand how to solve this type pf questions. I have the following input x and the labels. $Points$ $Label$ $(0,0)$ $1$ $(1,0)$ $1$ $(0,1)$ $1$ $(2,2)$ $-1$ $(3,3)$ $-...
0
votes
0answers
12 views

Simulated Regression - getting the population like data

I try to evaluate measures for Feature Importance for a regression. I have data set with highly correlated features. So the betas have a variance. This makes it difficult to estimate the "true betas" (...

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