# All Questions

137,827 questions
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### Is a single count data point significantly different from a set of reference count data

I have counted the number of occurrences of protein domains in the proteomes of 16 different insect species, 1 focal vs 15 reference species. For each of the ~4700 protein domains in my data, I have a ...
4 views

### Checking PH assumption for a time dependent (T_COV) variable in a Cox PH-regression: with or without the original covariate in the regression?

I am performing a cox proportional hazard regression on survival, in a sample in which almost everyone dies in the follow up period. I have little knowledge on statistics in general but i am reading ...
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### Ctree in R: how optimal is the optimal split point?

Hi I’m fairly new to using decion trees. I understand that to find the best split points, the ctree algorithm maximises a certain test statistic. I am interested to inspect the values of the test ...
36 views

### Wilcoxon signed rank test, getting a numerical media difference instead of p-value?

I have been running the Wilcoxon signed rank test, where my output is a p-value. Now, the p-value interpretation I am confident in, but I read in a paper that the authors reported the: The Wilcoxon ...
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### Regression analysis Interpretation [duplicate]

How do I interpret these results? Specifically, what does this regression analysis show us? How do we determine which values are statistically significant? I don't have problem with the coding. I just ...
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### this question is related to discriminant analysis

this is related to quadratic discriminant analysis. I want to prove the 11-13 using the result 11.2 as shown in the image.Can anyone suggest the steps to complete the proof?
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### Calculating the expected value of truncated normal

Using the mills ratio result, let $X \sim N(\mu, \sigma^2)$, then $E(X| X<\alpha) = \mu - \frac{\phi(\frac{a- \mu}{\sigma})}{\Phi(\frac{a-\mu}{\sigma})}$ However, when calculating it in R. I don'...
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### Compare model fit (-2 log likelihood), is my model significantly better?

I have 6 models with -2 log likelihood as an indication of model fit. The fit increases from model 1 to 6, with model 1 having the worst fit (lowest -2 log likelihood) and 6 the best fit. How do I ...
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### How to handle partial observations of the variable of interest when training a time series model?

I have the following time series data: $\{ t_i, X_i, Y_i \}$ where $i$ is the index, $t_i$ is the timestamp, $X_i$ the measured value of the external variable and $Y_{i}$ the value of the variable ...
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### How to approach machine learning time specific data; which months of usage to use?

I am relatively new to the data science area and just have a question about how to approach a time specific machine learning problem. Just as an FYI I am currently using a random forest classifier for ...
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### how to provide the lambda values to Glmnet in r?

here I want to perform Lasso-cross-validation on some data to find the optimal value of lambda. I chose the R platform and hence come across the Glmnet package in R. https://web.stanford.edu/~hastie/...
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### Proof of positive semi-definite: Chamberlin and Rothchind(1983) [on hold]

I want to ask following simple algebra from (1). Specifically, page 1295 there is an inequality equation to prove the characteristics of an inverse matrix of covariance. I want the answer regarding ...
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### What stats tests can be used to find whether the increase/decrease in counts yearly are difference statistically?

I have read posts about the similar problems in the forum and they are suggesting using regression to see if there is any significant increases/decrease. I have data for 3 years and their counts i.e. ...
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### Statistically compare similarity between images

I have two images/heatmaps (2d matrix) of identical size. I need to statistically compare the similarity between the two. With 'similarity', I mean that high and low values of one image appear in ...
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### Adjusted R^2 for regression with dummy variables

I'm familiar with R^2 and adj R^2 for penalizing the addition of predictive variables in a regression. I just want to double check that If I have three continuous predictor variables and 30 dummy ...
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### Equating two different sample sizes [on hold]

I have two scores, Score 1 and score 2. Score 1 has 150 samples and Score 2 has 85 samples. Is it possible to equate scores, especially using R packages?
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### online news readers engagement index (inverse of churn model?)

I would like to get a second opinion of the problem of assigning engagement scores to online news readers. Currently, I build a churn model as required by the company, that mainly predicts the ...
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### How to choose the best number of installments to sell an item

I have a dataset about previous sales. It contains both sold and cancelled item information. Which includes prices and number of installements for the item. Here I want to increase the probability of ...
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### Convolutional Conditional Variational Autoencoder Implementation

This may be a rather trivial question, but I am somewhat confused. I have been able to implement a convolutional variational autoencoder. I have also been able to implement a conditional variational ...
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### transformation of continuous variables in accelerated failure time model

Should I do some transformation of continuous variables in accelerated failure time model? In PH model it is needed and martingale residuals are helpful there. I know that PH and AFT models are equal ...
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### How to evaluate a model that outputs a range of values? [on hold]

Would you know how to compare the blue curve with the green interval? I try to evaluate my model (green curves) by comparing it with the true measure in blue, in order to know how accurate and ...
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### How to find the standard error of a sample of measurements each with their own uncertainity

I have a scale that has a resolution of +-0.01 grams. I have assumed that it has a standard error of +-0.005 grams. I would like to measure the mass of an Samsung INR18650-30Q battery. I would like to ...
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### INAR(1) simulation in R [on hold]

How do we simulate values of $Y_t$ for a maximum value of $t=60$ when we have an INAR(1) process as follows: $Y_t=ρ^*Y_{(t-1)}+R_t$ where $t$ takes values from 1 to 60, $ρ=0.3,0.8$, $ρ^*$ is ...
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### Linear Forecasting with a small dataset

I am trying to get some forecast (5 years more) from a small dataset that is as follows: ...
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### How is the frenet frame along an asymptotic curve related to the geometry of the surface? [migrated]

I'm reading Differential Geometry: A first course in curves and surfaces by Theodore Shifrin and here is one of the questions from the exercise. I just can't seem to make the connection between the ...
91 views

### Question regarding MLE

I have a question regarding maximum likelihood estimators/functions. I thought I understood the concept. But now i found an example of an Maximum likelihood function that i don’t get. The question is ...
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### Momentum updates average of g, Adagrad also of g^2 - any other interesting updated averages for SGD convergence?

Updating exponential moving average is a basic tool of SGD methods, starting with of gradient $g$ in momentum method to extract local linear trend from the statistics. Then e.g. Adagrad, ADAM family ...
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### Expected function evaluation of random variable w.r.t. different distribution

Suppose I have two continuous random variables on the same domain, $\xi \sim \mathbb{P}, \xi' \sim \mathbb{Q}, \in \Xi$ and joint probability $(\xi, \xi') \sim \Pi \in \Xi^2$ . Now I would like to ...
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### In the book “Applied Predictive Modeling”, why it repeats over the same fold when doing recursive feature elimination?

I'm trying to conduct recursive feature elimination (RFE) referring to Ch19.7 of the book "Applied Predictive Modeling" by Max Kuhn. In the book, it uses 5 repeated 10-fold cv for RFE. To do this, it ...
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### Does skipgram(word2vec) decreases the euclidean distance or increases cosine similarity between similar words?

The skip-gram model tends to predict the surrounding words or in other words, it tries to maximize the co-occurrence in the output of the Network. According to my knowledge, this makes a similar word ...
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### Neural network models in time series forecasting [on hold]

can we use NN models for non seasonal time series data like livestock population?
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