# All Questions

139,070 questions
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### student attendance prediction

I'm sorry for being such a nubie to all of this. Let's say I wanted to be able to predict, from game to game, what the total student attendance would be at an average college football game, where ...
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### Covariance matrix and persistence of excitation of input

Assume that a discrete-time system can be described by the following state-space equations $x(k+1)=Ax(k)+Bu(k)+w(k)$ where the input signal $u(k)$ is stationary and ergodic with $\mathbf{E}[u(k)]=0$....
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### Does someone has a good implementation of categorical focal loss? [on hold]

Does someone has a good implementation of categorical focal loss ? I'm not sure of existing package. Thanks
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### Alternatives to The Statistical Sleuth?

I am looking for a simple and concise book on statistics (t-test, ANOVA and all its variants, liner regression, etc.), centered on data analysis. I am not interested in theory or proofs, but just want ...
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### Image dimension reduction using pca

I have a 3000 of images each of which has shape of (200,180,3). I want to reduce their dimension. Therefore, I use PCA, I want to do it firstly without using any library. The first problem I camed ...
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### Which analysis should I use

I am comparing data from two cohorts of patients that underwent a surgical procedure: Group 1 (2013-2015, n=157) and Group 2 (2016-2018, n=146). In both cohorts, I have patients that had survived and ...
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### The questions is to be done using Binomial or Poisson distribution. Which distribution is to be used while doing this? [on hold]

A major warehouse facility has 10 semi-trailer loading bays, which can all be used simultaneously. On average only 7 bays are in use. ...
7 views

### Which test is better for variance analysis?

In the area of variance analysis, we have many options like student t-test, ANOVA and many more. Could anybody help me here, if we have to analysis the variance of a group of data, which test would be ...
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### Is “$\mathrm E[X'X]$ has rank $k$” the assumption of no multicollinearity?

My lecturer wrote this on the board: Assume $\mathrm E[X'X]=Q$ has rank $k$, where $X$ is the data matrix and $k$ is the number of independent variables. I asked her if that is the assumption of ...
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### Is an AR(p) process with roots inside the unit circle non-stationary? [duplicate]

The title pretty much says it all: is an AR(p) process with roots inside the unit circle non-stationary?
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### Repeated measures with rotation of subjects within groups

I was wondering if you could help with the interpretation of a potential experimental design. We are testing two versions of a 'group' exam, score (out of 100) being the outcome variable, aggregated ...
19 views

### How to compute confidence intervals from *weighted* samples?

Imagine we have a webserver, which serves a total of N static URLS. There are users visiting the URLs every day. At the end of each day, we have data like this: ...
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### How to interpret Estimated Marginal Means results

I have used the emmeans() package to calculated the difference between the difference of estimated marginal means. I did this by first calculating the EMMs of location|treatment, and then the ...
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### Mixing average and the Renewal Reward Theorem

I tried to solve the following problem: Buses arrive to an archeological site according to the discrete renewal process with i.i.d inter-arrival times T1, T2, T3, ... which are distributed Geo(p). ...
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### How to compare and select the better GARCH model?

I am reading this article which is talking about a GARCH trading strategy. I follow the steps and tried different parameters like window size (stock historical data). From the back test, I can see ...
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### What is the difference between a discrete and continuous rolling window?

What I have read so far suggests that a discrete rolling window is say a yearly window, calculating somethig every year, which is from 01-01/31-12 and a continuous rolling window is a window that ...
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### Computing slope of data with correlated errors using Monte Carlo method

I have $N$ pairs of $(x,y)$ measurements. I have the (estimated) uncertainty of each $y$ value as well as the correlations between each pair of $y$ values. I want to know whether there is a ...
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### Modified Mann-Kendall trend test on hourly data?

Hi have a ten year dataset of hourly readings of water quality parameters (pH, temperature, dissolved oxygen, turbidity and specific conductivity). Since the data is on an hourly basis, it probably ...