All Questions

0
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0answers
3 views

AICc for small sample size

I would like to test the effects of salinity and temperature on parasite infection. Temperature and salinity are the fixed factors, the first one has two levels, the second one three levels. ...
0
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0answers
3 views

What is the intuition behind the positional cosine encoding in the transformer network?

I don't understand how adding the cosine encodings/functions to each of the dimension of the word vector embedding enables the network to "understand" where each word is situated in the sentence. ...
1
vote
1answer
8 views

Including the outcome variable in multiple imputation

I'm trying to perform binary classification on a dataset with missing values. I used sklearn's iterative imputer to impute these values and I got pretty good results. However, I realized that I was ...
0
votes
0answers
3 views

Adjusting proportions for incidence

I have a set of enrollment percentages for every major ethnic group for a study I conducted about a disease I'm interested in. I have the age-adjusted annual incidence rates for that disease, for each ...
0
votes
1answer
11 views

In what situations would it be appropriate to use Ridge Regression vs Multiple Regression and vice versa?

My understanding is that regularization will generally help prediction tasks. What about for situations where we want to conduct a study to understand the effect of a specific predictor on the ...
0
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0answers
4 views

How to interpret the tests for weak instrument in R?

Stock & Yogo (2005) provide the rule-of-thumb that the first-stage F-test of an IV regression should be above 10 for the bias of the instrument to be less than 10%, and suggest to call weak an ...
0
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0answers
10 views

What type of accuracy should I reported in research paper?

I have read some research papers on the classification task of deep learning, and now I am doing my own. After investigating some research paper which also provided the source code for reproducing ...
0
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0answers
9 views

Machine learning for discrete probability distributions when events can be rare

I am following a paper which suggests using a restricted Boltzmann machine for learning a discrete probability distribution. I have encountered a problem, however, when the scientifically "interesting"...
0
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0answers
5 views

glmm (poisson or negative binomial) which explain the significance of each single level

I'm using the function glmer.nb of the library MASS to analyse the effects of two fixed factors (temperature: 2 levels and salinity:3 levels) and nested random factor (Individual ID/room) on parasite ...
0
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0answers
19 views

Can bagging outperform a random forest?

I want to predict wages and constructed bagged regression tree's and a random forest of regression Tree's. The bagged regression tree's outperform the random forest. Is this result even possible , I ...
1
vote
1answer
5 views

Robust two-sample test with triplicate measurements?

When testing for a difference in mean between two conditions, biologists typically use a $t$-test, and wring their hands endlessly about how to justify removing outliers. Whereas I typically use a ...
0
votes
0answers
6 views

Oversampling in Uplift Modelling

I hope any of you can help me in the following matter: I am about to write my master thesis addressing the question how response and uplift modelling differ in terms of performance but also the ...
1
vote
0answers
11 views

How can I do t.test when I don't have a null value?

I have a dataset containing 20,000 records of home sales. I'm asked Choose a numerical variable from your dataset. 1. Calculate a 98% confidence interval for the mean of this variable. I chose the ...
2
votes
1answer
14 views

significance of difference smooths

I am working to understand what is represented by the standard errors and confidence intervals of smooths of ordered factors. In this toy example, I wish to determine (1) the overall form of the trend ...
0
votes
1answer
20 views

GAN: Why can't we just use leakyRELU for discrete data to overcome vanishing gradient descent?

If we use a leakyRELU activation in the last layer of the generator of a generative adversarial network vanishing gradient descent won't be a problem at all in my opinion? But no one really mentions ...
0
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0answers
5 views

Which study design of R survey package to use with NAMCS dataset?

From official dataset documentation: ...
1
vote
0answers
6 views

Model with target as feature for benchmark

I was reading this article (https://towardsdatascience.com/predicting-the-popularity-of-instagram-posts-deeb7dc27a8f) about predicting the popularity of Instagram post using different techniques and ...
1
vote
1answer
16 views

Naming of mathematical elements in GMM?

I'm struggling with the naming of different elements in GMM. There doesn't seem to be consistency in the literature. What do we even call the moment integrand $g$? I take a stab below with help from ...
0
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0answers
12 views

Regarding interpretation of Odds Ratio

I have just read in my professor's lecture notes that the Odds ratio $\psi(x)$ takes non-negative values, and that the the effect of $X$ (the predictor) on $Y$ (the binary target variable) is measured ...
0
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0answers
18 views

Perpendicularity of random variables?

I am reading Bechavod et al. (2017) [1], and at page 3 there is written: In the example, each data point lies in $X = (X_1,X_2) = \{0, 1\}^2$ and has two features—$X_1 = A$ is the protected ...
0
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0answers
7 views

Can I say that the Factor, on factor analysis is the eingenvalue of the covariance matrix? [on hold]

Can I say that the Factor, on factor analysis is the eingenvalue of the covariance matrix ?
1
vote
1answer
16 views

What does it mean to have “groups” and “levels” of variables?

Using this website, a user can find a correct statistical test for their project. However, what do they mean when they write "2+ groups" or "2+ levels"?
0
votes
0answers
4 views

Identifying the difference between distribution when d > 1

Lets say I am measuring the velocity of wind at every 500m road segment (x) at time (t) on the Interstate 5. I classify each measurement into three clusters (...
0
votes
0answers
12 views

Do finite mixtures of normals have heavier tails than normal? [on hold]

Consider a finite mixture of normals $$f(x;\mu_1,\dots,\mu_n, \sigma_1,\dots,\sigma_n) = \sum_{i=1}^n \omega_i \phi(x;\mu_i,\sigma_i),$$ where $\sum_{i=1}^n \omega_i = 1$ and $\phi(x;\mu_i,\sigma_i)$...
1
vote
1answer
10 views

training a nn with f1 as loss on keras doesn't work?

I have no problem to train my neural network with categorical_crossentropy as loss but when I do the same with f1, it just doesn't progress : Epoch 1/9 1029/1029 [==============================] - ...
0
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0answers
3 views

Why ivmodelFormula and ivmodel give different results in R?

I stumbled upon an issue with the ivmodel package: when exogenous covariates are included in the model, the ivmodel function ...
0
votes
0answers
12 views

Multivariate regression for dataset with several dependent variables?

I'm looking at whether bottle size, design etc. has an effect on perceived value, perceived quality etc. So first set are the independent variables and the second are dependent variables. Would ...
1
vote
0answers
15 views

SEM: issue with two correlated latent variables

I am fitting a SEM model that includes socio-economic status (SES) for a household and environmental conditions (env) surrounding this household (road condition, sanitation etc). My (obvious) ...
0
votes
0answers
2 views

Compare canonical loadings across groups

Is it possible to statistically compare the factor loadings or canonical coefficients coming from a canonical correlation analysis run within each of two groups across both groups? e.g. statistically ...
0
votes
0answers
11 views

Generalized estimation equation distribution and link

Please fill me in. Thank you in advance. I have 3 response variables, 2 of them are positively skewed and have a continuous positive value while the rest is negatively skewed and have a continuous ...
0
votes
1answer
17 views

Empirial Bayes for means

I have data for US ~3100 counties where the variable is a mean score based on a sample. However, for many small counties, the sample size is quite small (like 5), and so these mean values fluctuate a ...
1
vote
2answers
19 views

In CNN, how to map from fully connected layer to output image?

In CNN, where the last layers are fully connected, how to make pixel-wise prediction to output an image(binary matrix), if the number of neurons in the last layer is less than the size of the image?
1
vote
0answers
8 views

Regression and Covariance Parameter Matrices in Multiresponse Gaussian Regression Using glmnet (R)?

I am new to using glmnet. How do you extract the estimated (sparse) regression and covariance parameter matrices in multiresponse gaussian regression using the glmnet package? There doesn't seem to be ...
0
votes
0answers
18 views

Using sigmoid in binary DNN output layer instead of softmax?

For a binary DNN, the output is $y_0 + y_1 = 1$ since they are the probability distribution, hence the sum must equate to 1. However, I've been told that $y_1$ is sufficient to represent the output of ...
0
votes
0answers
41 views

Mean and variance of $\tan^{-1}(\mathcal{N}(\mu,\,\sigma^{2}))$

How could we find the mean and variance of $\tan^{-1}(X )$ if $X \sim \mathcal{N}(\mu,\,\sigma^{2})$?
0
votes
0answers
7 views

Limiting number of independent variables in data before running linear regression [on hold]

I'm working with this dataset: https://www.kaggle.com/c/house-prices-advanced-regression-techniques/data and would like to use it to conduct linear regression (and maybe also Lasso or Ridge). After ...
0
votes
0answers
7 views

Interpretation of r and r squared in reduced major axis graph [on hold]

I have a correlation test where i used reduced major axis to get r and r squared, I am not sure though which value i should use for interpretation of the graph and what the difference is, because ...
0
votes
0answers
13 views

Sufficient Statistic and Unbiased Estimate in Exponential Family

I am reading this classic paper (Information and the Accuracy Attainable in the Estimation of Statistical Parameters) by CR Rao where he deals with sufficient statistics in exponential distributions ...
0
votes
0answers
16 views

Can Random Forests deal with variables that affect eachother?

I'm studying temporal aspects of a decision-related brain process. For this study I want to see how much the information (absolute amount of contrast and/or amplitude) of a stimulus at different time ...
0
votes
0answers
5 views

Identification of changing scope as formative constructs? [on hold]

Can scope creep/ requirement creep be evaluated as formative constructs?
0
votes
0answers
7 views

Factor Analysis PCA - Interpreting SPSS Pattern & Structure Matrix

I conducted a Factor Analysis using SPSS (see output attached). I used an oblique rotation (direct oblimin). How do I tell which variables load most highly on each factor?
1
vote
0answers
8 views

What derivative to use in Gradient boosting decision tree for a semi-supervised model

I am trying to build a semi-supervised prediction model with a Gradient Boosting decision trees. The learning phase is done using the following input: $X \in \mathbb{R}^{n\times p} $ $O(X) \in \...
0
votes
1answer
8 views

How to interpret precision and recall for multiclass prediction?

I have a few models doing prediction with 4 classes, with the output precision and recall varying with different labels. For example I have (with the class labels being 0, 1, 2, 3 on the x axis): I ...
0
votes
0answers
17 views

Proof for asymptotic error in logistic regression

Ng, A.Y., and Jordan, M.I. (2001). On Discriminative vs. Generative classifiers: A comparison of logistic regression and naive Bayes. Advances in Neural Information Processing Systems, 14, pp. 841-8, ...
0
votes
0answers
11 views

Machine Learning problem - label over multiple lines

Currently I'm trying to work out a project where I would like to recognize movements from videos using machine learning and python. What I've done so far is extracting the x and y values of body ...
1
vote
0answers
23 views

Volatility forecast with GARCH(1,1)

I am having trouble with this question: $Y_t = \sigma_t \epsilon_t$ $\sigma^2_t = 0.003+0.41Y^2_{t-1}+0.53 \sigma^2_{t-1}$ and I am given that $\sigma^2_T = 0.01$ and $Y_T = 0.2$. I am asked to ...
0
votes
0answers
11 views

Orginal logistic regression, regularisation and dummy variables

I have ordinal variables (Likert-scale 7 points) and categorical variables which are non ordinal (gender, age, vote, occupation, localisation). I created dummy variables for those. I want to know ...
0
votes
0answers
10 views

latent class model on choice data with gmnl - specify classes

I want to run a LCMNL (using the gmnl-package) on choice data. I know that with Latend Gold Choice 5.1 it is possible to specify classes in advance, so that the first class captures "random" choosers. ...
0
votes
0answers
8 views

How to calculate accuracy of model without having actual labels

i have a dataset having traing.csv and testing.csv files. i have trained the model on traing data and then predict the labels for testing data. as the labels are only given in training data. there are ...
0
votes
0answers
21 views

Find confidence interval of mean without knowing sample size?

In our calculation, we have only $\mu$ and $\sigma$ values. Is that possible to find the confidence interval of $\mu$ and $\sigma$, without knowing the sample size? As per our idea, we can calculated ...

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