All Questions

0
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0answers
9 views

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 ...
1
vote
0answers
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 ...
0
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0answers
9 views

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 ...
3
votes
2answers
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 ...
0
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0answers
23 views

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 ...
0
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0answers
6 views

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?
3
votes
1answer
302 views

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'...
0
votes
2answers
12 views

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 ...
0
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0answers
6 views

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 ...
0
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0answers
13 views

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 ...
0
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0answers
20 views

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/...
0
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0answers
9 views

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 ...
1
vote
1answer
35 views

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. ...
2
votes
1answer
28 views

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 ...
2
votes
1answer
14 views

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 ...
1
vote
0answers
18 views

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?
0
votes
0answers
9 views

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 ...
0
votes
1answer
7 views

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 ...
0
votes
0answers
10 views

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 ...
0
votes
0answers
7 views

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 ...
0
votes
0answers
11 views

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 ...
0
votes
0answers
7 views

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 ...
0
votes
1answer
22 views

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 ...
0
votes
1answer
25 views

Linear Forecasting with a small dataset

I am trying to get some forecast (5 years more) from a small dataset that is as follows: ...
0
votes
0answers
4 views

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 ...
2
votes
1answer
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 ...
0
votes
0answers
7 views

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 ...
1
vote
0answers
12 views

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 ...
0
votes
0answers
6 views

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 ...
0
votes
0answers
8 views

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 ...
0
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0answers
14 views

Neural network models in time series forecasting [on hold]

can we use NN models for non seasonal time series data like livestock population?
2
votes
0answers
23 views

$\text{Var}(\hat{y})$ versus $\text{Var}(y)$ for a general fitting algorithm

Suppose we wish to produce from a training set $(x_1, y_1), ..., (x_N, y_N)$ a fitted value $\hat{y}_i \approx y_i$. Let $\sigma_y = \sqrt{\text{Var(y)}}$ and $\sigma_{est} = \sqrt{\text{Var}(\hat{y})}...
0
votes
1answer
17 views

Is the t-interval and student's t-distribution the same?

I'm taking this course on statistical inference through datacamp. The instructor went over the idea of a confidence interval. The instructor said that we take a large number of bootstrapped samples ...
1
vote
1answer
53 views

Proving the MVUE is the following

I am stuck on the following question and I was wondering if can get some help. Let $f(x;\theta) = g(\theta)h(x),\ a(\theta) \leqslant x \leqslant b(\theta)$ with $a(\theta)$ decreases and $b(\theta)$...
2
votes
1answer
30 views

How do we deduce this fisher information relation?

Given a RS $X_{1},X_{2},\ldots,X_{n}$ whose distribution is well known (unless its parameters), how do we prove the following Fischer Information relationship \begin{align*} I_{F}(\theta) =\textbf{E}\...
0
votes
0answers
21 views

What's the right way to make a null distribution?

I want to run an a/b test. I'd like to check if my results in the experimental variant are extreme, under the null hypothesis. I haven't created my sample, yet, and I'd like to do a power analysis to ...
0
votes
2answers
24 views

For autoregressive time series modeling, does the AR(p) regressors have to be in order despite insignificance?

I am trying to fit a time series model using data of auto sales (DAUTONSA from FRED) and noticed that there is evidence of serial correlation. I’ve tried fitting a model with 4 lags but noticed that ...
1
vote
1answer
18 views

How can I compare how significant is the difference between three or more distributions of count data?

I am researching whether software developers use different numbers of communication channels when performing different activities. Therefore, I would like to know whether, depending on the activity, ...
0
votes
0answers
3 views

Fisher scoring of probit regression

Backgrounds We do know that for the logistic regression, which can be modeled $$ g( \mathbb{E} (y_i) ) = \log \left[ \frac{P(Y_i=1 |X_i = x_i)}{P(Y_i=0 |X_i = x_i)} \right] = \beta_0 + \beta_1^T ...
0
votes
0answers
7 views

What is matrix in year dummies ? Can we regress matrix in year dummy to a dependent variable only to get the residuals? [on hold]

I get confused by this concept I found on journal, It regressing a matrix of year dummy which I do not understand what is it. Does the year matrix dummy means we create a series that represent n-1 ...
0
votes
0answers
2 views

The use of cross validation in Dynamic Linear Model (or state space model)

The dynamic linear model has the form as $$ y_t = m(\theta_t, x_t) + \epsilon_t ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ (1)\\ \theta_{t+1} = F \theta_t + R \eta_t,~\eta_t \sim N(\mu_t,\Sigma_t) ~~~~~~(2) $$ ...
0
votes
1answer
27 views

Interpreting lme4's interaction effects in linear model

I am struggling to understand how lme4 reports interaction effects and how to interpret what is reported. I know there are a ton of lme4 questions and answers on this site, and I'm trying to read ...
0
votes
0answers
5 views

proportional hazard assumption

What is the assumption we must check if Cox proportional hazard regression is used? Is my step and method to build on Cox proportional hazard model correct, or not? Can I used ln(-ln(survival))curve ...
0
votes
0answers
4 views

Deriving P value formula for UMP size-alpha test [on hold]

Let X1, . . . , Xn ∼ iid N(θ, σ2), and we wish to test the one-sided hypotheses H0 : θ ≤ θ0 vs H1 : θ > θ0. (a) If σ2 is known, we can use the UMP size-α test. Find the formula for the P -value of ...
0
votes
0answers
5 views

Applying CRF to semantic segmentation

Confused on how to apply CRFs to semantic segmentation. I'm not able to find any good tutorials except this one. Is the process the following: First train a DNN on some training set. Generate ...
0
votes
0answers
15 views

How do you model a null hypothesis? [on hold]

I understand that, in hypothesis testing, the idea is that you create a sampling distribution under the null hypothesis and then you conduct an experiment. Your value falls on some part of that ...
0
votes
0answers
6 views

Repeated Measures with Nested Random Effects [on hold]

I'm working on a study involving cookie recipes. There are 3 levels of sugar: half, normal, and double. Within each level of sugar, there are 3 random batches, labeled 1 to 9. On 3 consecutive days, 5 ...
0
votes
1answer
19 views

limit and stationary distribution of a Markov chain

Consider a Markov chain on the non-negative integers with transition probabilities 􏰀$1/2$ if $y=x+1$ and $1/2$ if $y=0$. Find $\lim_{n \to \infty} P(X_{n}=0)$. Is this limit the same as the ...
0
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0answers
7 views
0
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0answers
45 views

Understanding the GAN Loss function from the original paper

I've been reading the paper Generative Adversarial Nets by Ian J. Goodfellow et al., to have a more deeper understanding about the concepts from the author's perspective (I do understand the basics of ...

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