All Questions

0
votes
0answers
10 views

forget_bias interpretation in tensorflow

In Basic LSTM cell of tensorflow there is an argument named forget_bias. From the documentation of ...
1
vote
1answer
19 views

clustering with KL divergence

Recently I read some papers which related to clustering. The paper is https://xifengguo.github.io/papers/ICONIP17-DCEC.pdf In this paper, they calculate Loss function as KL Divergence, KL(P||Q). ...
0
votes
0answers
3 views

Selection criteria for penalty parameters in the ridge multinomial logit model

I appeal to you for the following doubt. I am adjusting a ridge multinomial logit model but I have problems in the criterion when choosing the lambda parameter that gives better results, besides ...
0
votes
0answers
5 views

How to show that cov(Yi, Y-bar)= (σ(^2) y)/n

I'm trying to figure out how to do this proof, and then use it to show that sample variance is an unbiased estimator.
0
votes
0answers
4 views

Visualizing separability / independence

I’d like to visually ‘see’ the independence of random variables. I tried plotting f(x), f(y), and f(x, y) for independent and dependent pairs of variables. However, the difference is still not ...
0
votes
1answer
8 views

Estimating Differential entropy from unbiased samples of a probability distribution

If I can get N unbiased samples $x$ from $p(x)$ how can I approximate the Differential entropy: $$H(X) = -\displaystyle\int_{x} p(x)\log p(x) dx$$ I'm not very knowledgeable in statistics so I'm not ...
0
votes
0answers
5 views

Advice on ML ideas/models for a data set I have

I have a very large marketing data set (300GB in size) and I am wondering what ML models I can apply to it. The dataset consists of transactional data from supermarkets. The type of data I have is the ...
0
votes
0answers
7 views

Correlation above 1 between second-order and first-order latent variable

So I ran CFA on an exhaustion measure comprising of three facets which were specified as first-order latent variables. When I added a secon-order latent variable to the model the correlation between ...
1
vote
1answer
335 views

zero conditional mean assumption coupled with random sampling assumption (deriving unbiasedness)

I don't get part of the explanation of deriving unbiasedness of OLS in my textbook. I understand that to derive unbiasedness we have to use conditional expectation (conditioning on $x$) so that the ...
1
vote
1answer
96 views

How do you interpret the Cliff's delta & 95% Confidence Interval (2−tailed) graph?

I've recently just completed a cliff's delta on a data set containing ordinal data (Strongly disagree to strongly agree), and have graphed the results. I'm just a little wary over how to exactly ...
2
votes
1answer
5 views

How to conduct power analysis for unbalanced one-way ANOVA in R?

I am looking for a way to conduct power analysis for unbalanced one-way ANOVA in R. I found the pwd package; however, it only allows me to calculate power for ...
3
votes
2answers
38 views

Steps of Matrix Multiplication

It may seem kind of silly, but can anyone please show me the intermediate steps implied by the second equality in this derivation? $$e^\prime e = \left(y - Xb\right)^\prime\left(y - Xb\right) = y^\...
1
vote
1answer
32 views

How do you select the best from a number of linear models?

I'm learning linear regression with the Carseats data set. I went through the data, cleaned it, encoded the dummy variables and checked for collinearity. The dataset has 400 observations on Carseat ...
0
votes
0answers
3 views

Data exploration to determine if GAMs are appropriate

How to decide, based on data exploration, between a GAM and a GLM. Linear Models (LM) assume that the relationship between the response and the predictor are linear. Generalized Linear Models (GLM) ...
0
votes
1answer
334 views

repeated cross-validation shows similar results for different k-folds

I need to see whether different k-fold cross-validations with repeats will improve my classification accuracy. For that, I have tested with repeatedCV (...
1
vote
0answers
6 views

Weighted covariance with different reliability weights?

Suppose observables $X$ and $Y$ possess different reliability weights $w_{x,i}$ and $w_{y,i}$ for the possible elements $x_i\in X$ and $y_i\in Y$ respectively. Considering a sequence of consecutive ...
1
vote
1answer
38 views

How to determine sample size for chi-quared test?

Similar questions have been asked here on CV, however I have not found a solution to my specific question yet. I am trying to plan a sample size for chi-squared test. However, I struggle to find the ...
14
votes
3answers
946 views

How can I model flips until N successes?

You and I decide to play a game where we take turns flipping a coin. The first player to flip 10 heads in total wins the game. Naturally, there is an argument about who should go first. Simulations ...
1
vote
1answer
21 views

Out-of bag error in Random Forest

I am trying to code my own, simple version od RandomForest function in R for learning purposes. However I have a hard time understanding the concept of the out-of-bag error. Is it simply done by ...
0
votes
0answers
2 views

GWAS genotype/phenotype datasets for supervised learning model testing

I'd like to play around with several ML models and test their predictive power using some good datasets. I need datasets of genotype (a set of SNPs) and phenotype (some trait). If possible, I'd ...
0
votes
0answers
9 views

I am facing the same error [on hold]

mydata3=mydata2[,c(2,4,7,9)] set.seed(123) model <- train(fwd_def_status ~., method = "rpart" , data=mydata3) What to do in the case where my dependent var is part of mydata3?
0
votes
1answer
34 views

Derivation of Formula for linear regression with data points forming a circle

Suppose we have one dimensional data with following conditions.1. The value of this single feature lies in the closed interval [-a,a].2. The associated target value with each data also lies in the ...
0
votes
1answer
334 views

Latent Dirichlet Allocation Topic Word Distribution

I trained a scikit learn LDA model on 400 000 documents of about 50 words each. I then took a look at the final topic word distribution by computing the cosine similarity matrix of the given topics. ...
1
vote
0answers
4 views

Unit-root and Johansen- lack of normal distribution. Please help!

I have a question concerning unit-root data and normal distribution. As an assignment, I am checking the long-term relationship between unemployment rates and labor force participation rate. First I ...
0
votes
1answer
20 views

Is it reasonable to display “percentage data” in a boxplot, why?

I have data that are in fact percentages of C (bound to clay) combusted in a certain temperature interval. Exemplary data: ...
0
votes
1answer
20 views

How to use last predicted value as feature? NLP NER mission

I'm performing NER (Named entity recognition) For example: Seq: When Donald Trump announced... Tags: O B-Person L-Person O When I'm predicting ...
0
votes
1answer
11 views

What test for a 4-level categorical variable and a continuous variable?

I'm currently doing research on whether image quality affect engagement. Image quality is given in 4 categories (bad, benchmark, semi-professional and commercial level) and engagement is in how many ...
2
votes
1answer
328 views

Decide right number of clusters when clustering high-dimensional sparse binary data

I am trying to clusters points in a high-dimensional space (5000 features for each data point). Each feature can take 0 or 1 value. Also for each point only a small subset of the features will be 1 (...
0
votes
1answer
15 views

Differences in calibration plots for machine learning models

I'm using machine learning methods in R for descriptive regression modelling of a small dataset. I have fit random forest (randomForest), unbiased random forest (cforest) and boosted regression trees (...
1
vote
1answer
6 views

how should I specify a deterministic trend in my time series data?

How can I specify a trend (term) in my time series data? does it have a logical procedure or is it totally base on visual interpretation of historical plot?
0
votes
1answer
14 views

What measure should I use as cross-validation error with logistic regression in K-fold cross-validation?

What measure should I use as cross-validation error with logistic regression in K-fold cross-validation, especially when the Type I error is more serious and what we want to avoid at all cost?
0
votes
1answer
10 views

What is the difference between SSIM and MS-SSIM?

I would like to know what is the difference between SSIM and MS-SSIM? Also, there is a built-in function in Tensorflow for both of them, I am curious to know when should I use SSIM and when MS-SSIM? ...
2
votes
1answer
20 views

slice sampling correctness

Theoretically, the slice sampling has equilibrium distribution as the target distribution. If we can sample exactly as follows, $y' = U(0, p^*(x))$ $x' = U\{x: p^*(x) > y' \}$ However, in the ...
2
votes
1answer
308 views

Statistical differences between two hourly patterns

I have 2 groups of subjects, namely: Subjects that are younger than 67 Subjects that are older than 67 Each subject of each group wears a sensor that estimate the metabolic equivalent of tasks (METs)...
0
votes
0answers
13 views

Unable to remove heteroscadasticity

This is my model: lm(PCTUI~year+statefips+factor_agecat+factor_sexcat+factor_racecat+factor_iprcat, data = train) I have factorized the categorical variable. ...
1
vote
0answers
12 views

Asymptotically unbiased estimator vs consistent estimator

I'm wondering if there is a difference between an asymptotically unbiased estimator and a consistent estimator. For asymptotically unbiased estimators, the expected value of the estimator converges ...
0
votes
1answer
18 views

multiple one sample t.test with ANOVA

If I want to see if the mean of 3 different groups is above a specific threshold instead of doing 3 on-sample ttest can I use anova? So instead of 3 ...
0
votes
0answers
5 views

how to use Likert Scale to prove hypothesis

How to use data collected from likert scale (five point) to prove hypothesis. For example. Hypothesis 1: Internet marketing is cost efficient. Statement 1: internet marketing required less budget. ...
0
votes
0answers
12 views

Use PCA in order to show impact of variables on clusters

I did a clustering of selected variables. Is it possible to use the PCA (contribution, correlation) in order to show the impact of each variable in the clustering? (cfr. image 1) and add complementary ...
0
votes
0answers
8 views

How many parameters are in this specific model

I am planning on doing Structural Equation modeling on the following model that is pictured: I am trying to calculate my needed sample size. I have read the rule of thumb is 200 for SEM or 20 cases ...
-1
votes
0answers
31 views

PDF of $\frac{(X_1-X_2)^{2}}{2}$ where X1 and X2 are independent standard normal [on hold]

I'm trying to find the PDF of $$\frac{(X_1-X_2)^{2}}{2}$$ where X1 and X2 are independent standard normal. Any hints on how to proceed with this?
24
votes
4answers
17k views

What is the relationship between regression and linear discriminant analysis (LDA)?

Is there a relationship between regression and linear discriminant analysis (LDA)? What are their similarities and differences? Does it make any difference if there are two classes or more than two ...
0
votes
0answers
37 views

Probabilistic user behavior markov models on web

I am considering the following probabilistic Markov model of actions of a user on the results page of a search engine. The user examines the first result, with a probability $A$ he is satisfied with ...
0
votes
0answers
5 views

Rescaling Linear Impulse Response Functions, Innovations, and Confidence Bands

all. I am using a VAR model to do a bit of analysis. I obtain cumulative (linear) orthogonalized impulse response functions (COIRF). Because I am conducting similar analysis across different time ...
0
votes
1answer
18 views

Do these standardized residuals show heteroskedasticity?

I'm practising in the individuation of heteroskedasticity from the standardized residuals. I know that, if the time series is homoskedastic, the spread of the residuals should be constant and random ...
3
votes
1answer
303 views

Inconsistent results when try get the best k in KNeighbors

I'm trying to get the best k from iris dataset using KNeighbors so I write the below code using scikit-learn. ...
0
votes
1answer
23 views

When should we use the segregated as opposed to the aggregated data?

In the book "Causal Inference In Statistics" by Pearl et al., there is the following problem (study question 1.2.2.) A baseball batter Tim has a better batting average than his teammate Frank. ...
0
votes
0answers
3 views

What type of R-squared measure should I use? [on hold]

There are several R-squared types out there for generalized linear models. As far as I know, the choice of R-squared depends on the error distribution assumed and the link function used. So my ...
0
votes
0answers
4 views

Nested models and ANOVA: F ratios

I have some commuting data involving a factor B (district) that is nested inside another factor A (city). I am assuming both factors are fixed. I have calculated F ratios involving $MS_A/MS_R$ and $...
0
votes
2answers
27 views

Calculating Poisson CDF

I have a very dumb question about Poisson CDF. I have the following function $P(x;\mu)$ referring to the Poisson CDF. Hadley and Whitin (1963) defined the Poisson density as $p(x;\mu)= \frac{\mu^x}...

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