All Questions

Filter by
Sorted by
Tagged with
0
votes
0answers
4 views

Auc measure for Local outlier detection in python

I'm using Local outlier factor algorithm provided by Scikit-learn for outlier detection. For the evaluation i want to use auc measure. ...
0
votes
0answers
5 views

Test Hypothese of a given problem

Hi guys I found this problem in an old book but cant seem to find a solution to it. To be honest I dont really have much of an idea how to go about it. I am trying to study statistics on my own. Can ...
0
votes
0answers
4 views

Calculate Bayesian point estimator and the Likelihood estimator

Hi guys I found this problem in an old book but cant to find a solution to it. To be honest I dont really have much of an idea how to go about it because I am trying to study statistics on my own. Can ...
0
votes
0answers
3 views

Interpreting coefficient changes in Cox PH model involving interactions

I read the relevant questions here involving interactions in CoxPH (including 1, 2, 3, 4, 5, 6), and the relevant chapter of Applied Regression Analysis and Generalized Linear Models textbook. However,...
0
votes
0answers
6 views

How to explain intuitively to a lay audience that the variance is an unbiased estimator?

I have data for the concentration of several chemicals in the milk of 10000 cows and have to explain to policymakers and the lay public (i.e. people with no or limited knowledge of statistics) that ...
0
votes
0answers
4 views
0
votes
0answers
4 views

Scaling different datasets for comparison - Increasing signal 'gain'

I have 4 protein microarray datasets that I am trying to compare. I have concocted a method of aligning them all and comparing them all on a continuous scale which seems to have worked well. These ...
0
votes
0answers
11 views

How to check if parameters from non-linear curve fits on two datasets are statistically significant?

I have two datasets. They measure a physical response Y (in a certain sample) with increasing concentrations (X) of a certain molecule (dose response). I fit my datasets to a model known as one site ...
0
votes
0answers
3 views

Can I have a moderator in 2-1-1 multilevel mediation? If so, the moderator should be at Level 1, Level 2 or both? What are the HLM formulas?

Can I have a moderator in 2-1-1 multilevel mediation? If so, the moderator should be at Level 1, Level 2 or both? What are the HLM formulas? To test the interaction effect, can I create the variable ...
0
votes
0answers
15 views

Statistical term for distribution spanning zero

Is there a statistical word for a data distribution that spans zero? For instance, 'sentiment' data distributions can hypothetically range from negative to positive. The value distributions might be ...
-1
votes
0answers
14 views

How to calculate the Maximum-Likelihood

Hi guys im starting to study statistics on my own and found this problem on a exam paper but cant seem to find the answer of it. Can anyone help me please? Let $X_1, . . . , X_n$ be the random ...
0
votes
0answers
5 views

How does the Friedman test's average ranks for this data have been calculated?

I have used KEEl tool and another statistical tool to perform the Friedman test. However, these tools returned different results for the average ranks. How does these values have been calculated? The ...
0
votes
0answers
8 views

R Caret - Random Forest with repeated CV

I am currently struggling to explain the combination of bagging and cross-validation. I am aware of what each does separately but I have difficulties to explain how they are combined (if at all). For ...
0
votes
0answers
12 views

Is there any valid way to compare two linear mixed effects models based on two different datasets?

I am a Master's student and currently analyzing 2 datasets with reading times as dependent variables. For the first dataset, I used a blocked presentation of the linguistic and visual stimuli, while ...
0
votes
0answers
5 views

Growth Curve Modeling Using SAS Software Program

The analytical strategy of the study is to define a linear growth curve model for volume measured at three time occasions and also to investigate the influence of therapeutic intervention for a type ...
0
votes
0answers
3 views

How do we obtain the combined level's HR or OR in a regression model?

I would like to perform a cox PH model. I have identified 4 covariates to investigate the association with survival time. 2 of the covariates are trauma and ...
0
votes
0answers
13 views

is k-fold cross validation suitable for time series data?

I made a prediction model on time series data using the SVR method then to determine the best parameters I used the gridsearch algorithm and k-fold cv using the R software by default. The data that I ...
2
votes
0answers
9 views

Linear mixed effect model - heteroskedascity interpretation

I have a dataset with speed difference between men and women on several race distance. The data structure look like this. ...
1
vote
0answers
9 views

repeated measurements needed for certainty

A bit of a silly question. We have a model, which can be described as y = M(x) + some significant levels of noise. We see that if we repeat the measurements of y N times, we can see a clear ...
2
votes
1answer
13 views

How to write a joint kernel density?

Consider two random variables $X$ and $Y$ with densities $${f}_1(x) = \frac{1}{nh_1} \sum\limits_{i=1}^nK\left(\frac{x-u_i}{h_1}\right) ~~~~\text{and} ~~~~ {f}_2(y) = \frac{1}{nh_2} \sum\limits_{j=1}^...
0
votes
0answers
2 views

Reporting Heterogeneity in SAH

I am doing research on reporting heterogeneity in self-assessed health between different subpopulation groups of a country. I have one variable (categorical, discreet) that I want to test using ...
0
votes
0answers
5 views

LibSVM: Understanding the data format [closed]

I am currently experimenting with the LibSVM format as standardized format for exchanging label/feature data sets between Python and Java in a Spark project. However, I am a bit confused by the ...
0
votes
0answers
6 views

Maximization of correlation coefficient. The canonical correlation

The idea of the Canonical correlation is to maximize the correlation between two vectors $(Y,X)$ usign 2 vector of weights $(\alpha,\beta)$. My problem is that I have a dipendent variable $Y$ and a ...
0
votes
0answers
10 views

Changing the parameter values inside a function using if/else statements? [closed]

I have a function in the form of a power law. I want the power in the function to change depending on if the input value is greater than a certain turnover value inside the function. Here's what I ...
0
votes
0answers
10 views

Which model to use for multiple outputs in classification problem

I want to predict roles based on name, experience, soft skills, technical skills . Based on all these variables I want to ...
1
vote
0answers
7 views

Estimating Time to failure when there is no failure pattern

Assume I have data from some sensors and the goal is to estimate the failure time, however, some sensors never fail, and the question is what label to assign to those sensors. For example, consider: ...
0
votes
0answers
14 views

How is the Following Picture Possible?

Source: https://blog.wolfram.com/2013/03/21/the-mathematics-of-queues/ In this picture, it would appear that multiple customers can enter and exit the queue at the same time. In real life, this is ...
0
votes
0answers
9 views

Binomial Proportion Test on test and control populations

I am new to statistical tests and request your help with the following question: A company wants to test the hypothesis that it's new ad will increase it's total number of subscribers (conversion rate)...
0
votes
0answers
8 views

Recommnedation for books and material for solving differerntial equations through neural networks

I was going through some past and recent papers on using neural networks for solving ordinary and partial differential equations. One of the fascinating papers that inspired a flurry of papers is ...
0
votes
1answer
16 views

interpretation of one sample t test in r

I would like to understand the interpretation of One Sample T test in R. This is my code x <- rnorm(100) qqnorm(x) qqline(x) t.test(x,mu = 5) I have used ...
1
vote
0answers
15 views

What can we infer from the sample size and mean?

I came across this interesting question today and haven't been able to understand how the statistician was able to arrive at the estimate: A sample of 300 customers were asked to participate in a ...
0
votes
0answers
11 views

Can I regress overlapping independent variables?

give cash coupon give non-cash coupon Brand B Item A Item B Non-Brand B Item C Item D give cash coupon ratio= (item A Sales volume + item C Sales volume)/ total sales Brand B sales ratio = (item A ...
1
vote
1answer
15 views

Why to put variance around the mean line to the definition of $R^2$? By what is this particular choice dictated?

Suppose we have a linear regression and we calculate $R^2 = 0.81$. That means $81\text %$ less variance around the regression line than mean line, since $R^2 = \frac{\mathrm{Var\ (mean\ line) - Var\ (...
-1
votes
1answer
27 views

Is the Mann Kendall test still effective with a lot of NA?

Recently I need to test the trend of a time series from 1665 to 1991 and I am going to use the MannKendall test in R. However, I finally found that I only have 210 values instead of the whole 256. ...
0
votes
0answers
6 views

The critical thinking about the "staying forever" in Difference-in-Differences estimator of differential timing setting?

When dealing with the differential timing DiD setting, we may apply some modern approaches like Callaway, 2020, Borusyak, 2021 (I focus more on the imputation estimator of Borusyak because I am using ...
0
votes
0answers
7 views

Least Squares Etimates of Simple Linear Regression with Three Level Categorical Variable

For a simple linear regression model with a binary categorical variable: $$y_i = \beta_0 + \beta_1 x_i + \epsilon_i.$$ The least squares estimate are: $$\hat{\beta}_0 = \bar{y}_0 \; \text{and} \; \hat{...
0
votes
0answers
6 views

What is the variance of a constant and set rate?

Say we have two options: 1-out of every 25 videos, one will be promoted 2-every video has a 4% chance of being promoted For the first example, it's meant that after 25 videos, it's guaranteed that ...
0
votes
1answer
15 views

Computing probability distributions over bootstrap samples for two statistics

I have a data set $x= c(0.9575,0.4950,0.1080,0.9359,0.6326)$ and I'm trying to compute the probability distributions for the statistics $\bar X^* - \bar X$ and $\sqrt n(\bar X^* - \bar X)/s^*$, over ...
0
votes
0answers
6 views

Differential entropy of a kernel density estimator

I have a set of (~500k) observations that I use to fit a parametric model (univariate three-parameter lognormal). To have an idea of the goodness of fit, I want to compute the Jensen-Shannon distance ...
0
votes
2answers
42 views

If ε or error rate is normally distributed $N(0, σ^2 )$, why is y also $Y ∼ N(µ, σ^2 )$?

I have the following notes which describe a basic height model: If Y has some distribution with mean µ and variance $σ^2$: E(Y) = µ, Var(Y) = $σ^2$ then this can be written: Y = µ + ε i.e. Data = ...
1
vote
0answers
17 views

Find conditional expectation given symmetric r.v

How to find $E[sin(X)|cos(X)]$, if X - a symmetric random variable? My attempt: I tried to prove that $sin(X)$ is $\sigma(cos(X))$-measurable. Then it can be argued that $E[sin(X)|cos(X)]=sin(X)$. But ...
0
votes
0answers
11 views

Simple Linear Regression with Three Level Categorical Variable

Let the following regression equation: $$Y_i = \beta_0 + \beta_1 X_i + \epsilon_i,$$ where $X_i$ is a dummy variable. By setting $X_1$, $X_0$, $Y_1$ and $Y_0$ the variables $X$ and $Y$ when $1$ or $0$ ...
0
votes
0answers
20 views

Expectation for a function of a discrete random variable

This is a bit on the elementary side, but I'm having trouble understanding if the following formula is a definition, or a derivation. Given that $E[X] = \sum\limits_x xp(x)$, and $g(X)$ is some real-...
3
votes
1answer
138 views

Why the standard error of the mean never gets to zero even when the sample has the same size as the population?

Why, when we calculate the standard error of the mean for a hypothetical sample with the same size as the population, the value is not equal to zero, if the sample in this case is identical to the ...
0
votes
1answer
11 views

Intercept of logit vs intercept of multinomial logit

If I simulate the success probability for a Bernoulli random variable $t_{binary}$ conditional on some regressor $x$: ...
0
votes
0answers
19 views

Show that the weights in IWLS algorithm are always 1

I have a data for fire insurance with a model with the responce variable Y claim size and there are two potential predictor. I have to fit the linear additive model $$E(log Y_i)=\beta_0+\beta x_{i,grp}...
1
vote
1answer
15 views

Mode for equal consecutive frequencies

I'd like to calculate the mode for the frequency distribution table: ...
0
votes
1answer
15 views

Dimension selection based on test accuracy

consider that I have a dataset with train, validation and test set and I want to train the pipeline PCA+logistic regression classifier. So far, for a specific k (that is the reduced data dimension ...
0
votes
0answers
10 views

How can you express the average treatment effect on the treated (ATT) in Pearl's do notation?

How can you express the average treatment effect on the treated (ATT) in Pearl's do notation? Would it be $E(Y|X=1,do(X)=1)-E(Y|X=1,do(X)=0)$?
0
votes
0answers
5 views

Is it possible to verify that washout period was sufficient? And find out if it can be shortened?

Is it possible to use the data collected during the washout period to verify that the length of the period was sufficient? The carryover effect was not significant (we did not expect a carryover ...

15 30 50 per page
1
2 3 4 5
3701