# All Questions

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### Several Questions About "Prioritized Experience Replay"

I have 3 questions about "Prioritized Experience Buffer" as described in the paper. what's the point of the importance sampling (IS)? I'll explain - I understand that: a. when we ...
• 223
1 vote
10 views

### I have a solution, but I want to understand it - why is this a Markov chain?

In the era of the modern internet, many students, myself and my cohort all included, are exposed to answers to homework nearly as quickly as we are assigned it. Obviously this can be very detrimental. ...
8 views

### Inferences about mu based on the sum of two dependent normal RVs

Given: $X \sim \mathcal{N}(\mu, \sigma^2)$ $Y \sim \mathcal{N}(0, (\theta X)^2)$ $Z = X + Y$ I want to be able to make hypothesis tests or confidence intervals for $\mu$ using $Z$ and known $\theta$ ...
1 vote
30 views

### The asymptotic distribution of a Pearson Chi-Square test statistic (test for independence)

There are many different Pearson Chi-Square tests. The test statistics are always a sum of scaled and squared deviations. Some are written as a single sum, and some are written as a double sum (the ...
• 19.2k
15 views

### Looking for practice problems with answers [closed]

I have an exam soon which will be tested on the material from chapters 1-4 of this book: https://www.utstat.toronto.edu/mikevans/jeffrosenthal/ (the contents of each chapter can be seen for free with ...
• 113
6 views

### In a specifically ordered set of binary data (ones and zeros), how can you organize them in patterns and from there build a probabilistic network?

So I have a set of 1s and 0s. They are listed in a column on excel. They are listed in a specific order. I do not wish to change their order. So they appear as (1, 0, 1, 0, 0, 1 and so on... 0). Here ...
11 views

### Error with cuminc ("unused argument") [closed]

Hopefully simple question. Trying to look at competing risk analysis for my data, and keep running into the same error with using the cuminc function (part of the <...
1 vote
29 views

### Finding a non-symmetric test for correlated random variables $A$ and $B$ where $B\ge A$

Let's say I randomly sample pairs of numbers, $(A, B)$, each within a range of 0 to 10. In every pair, $B \ge A$. If I were to graph these points, they would fill only the half of the square that lies ...
• 11
18 views

### Calculating Cohen's d

I have two groups (experimental and control) and a measure (an estimate of confidence) measured at baseline and at post-intervention. I have ran a multiple regression and found that the intervention ...
• 131
6 views

### Single event prediction using multivariate time series data

I want to predict a single event by using multivariate time series data. The event I am going to predict is 100% going to happen in the following weeks but not sure when. And this event is going to ...
• 1
5 views

### Given multiple ordinal leaderboards, test if an attribute has an effect on the ranks?

Consider that we have a game that results in an ordinal leaderboard. Now, play $N$ rounds of that game, with different number of players. I want to know if a nominal attribute of the players has an ...
19 views

### How does one create comparable metrics when the original metrics are not comparable?

The problem I have is that I have several groups (say 3 to make discussion concrete) with observations from a true but known distribution $p^*_1, p^*_2, p^*_3$ (or 3 populations). I can compute some ...
• 6,316
31 views

### Probability mass function of floor of some continuous distribution

Say, we have a continuous random variable $X$ with pdf $f(x)$ and corresponding CDF $F(x)$. We are interested to get the pdf of $Y = \lfloor X + 1/2 \rfloor$. Is there any specific rule to obtain pdf ...
• 819
14 views

### Blinder-Oaxaca Decomposition: Components not adding up

As part of an analysis I am conducting that aims to understand the determinants of female labor participation, I ran a Blinder Oaxaca Decomposition for a specific region in my countrywide data set, so ...
41 views

### Why do I sometimes see the expectation E, probability P and distributions written in blackboard bold?

For example, $\mathbb{P}(X = 1)$ rather than $P(X=1)$ And for example:
13 views

### Econometrics Random Effect moddel

In R, I wrote the following lines of code - I need to "translate it" into a mathematical expression : ...
30 views

### which LME model to use?

I am interested in learning whether a diet can help people lose weight. I randomly assigned  participants to receive the new diet. Weight was monitored at baseline  and again at the beginning of every ...
9 views

### Defining censoring level in survival analysis

I'm conducting a simulation analysis using the Exponential, Weibull and Gompertz distribution. To get the times I'm using the table from Austin 2012. But how can I define the censoring level to be ~...
• 47
1 vote
32 views

### Beginner question: What degree of freedom to use in a particular case of variance calculation?

This is a beginner question (I think), and I apologize if it's not even correctly posed. REDO There is a process to smooth Raman spectra. This process assumes that the Raman spectra data consists of ...
• 111
22 views

### Why do we have 2 forms of the Z-table but only 1 of the T-table?

From my question here I understand that we only have 1 form of the t-table so as to save paper. We are meant to imagine the form with negative T-scores. (Even though this is not stated on the t-table ...
• 579
33 views

### Doubt in empirical distribution, sample and random variable

I have a basic doubt in sample and random variables. I have read related posts on this site but still some doubt is still left. Suppose we have a population and we are drawing some entries from it ...
• 103
11 views

### In Weka, how can I use GridSearch to fine tune 5 algorithms? [closed]

In Weka, I want to apply 5 algorithms (NB, SVM, LR, KNN, and RF). Further, I want to fine-tune their parameters by using GridSearch. My question is: How can I know the values of their parameters?
25 views

### What is the relation between permutation and combination in ${}_nC_k$?

Let suppuse that we flip 3 coins The possible outcomes will be: We use the formula $n!$: So if $K = 2$ Then $K!$ is So how is related this: with this:
• 164
18 views

### Statistically significant AR(1) coefficient, but insignificant coefficients when calculating ARMA(1,1). Why?

I'm using the library statsmodels with a simple financial time series to calculate the coefficients for an AR(1) model, and a ARMA(1,1) model. In the first case the L1 coefficient is statistically ...
9 views

### Is there a difference between out-of-domain and out-of-distribution?

When I research papers on the generalisability of ML models, both terms "Out of Distribution" and "Out of Domain" pop up. Are these essentially the same? In my understanding, yes. ...
19 views

### can cross-validation solve the issue of confidence interval interpretation?

I want to approach a true parameter value, and my chances of obtaining it, but I struggle to accept the subjectivity of bayesian credible intervals just as much as I can't see the value of a normal ...
• 1
13 views

### Averaging compound growth rates is giving incorrect results

Let's consider two stocks with the following prices for a three days period: Stock 1: day 1: 100 day 2: 105 day 3: 110 Stock 2: day 1:100 day 2:100 day 3:110 ...
12 views

### my dreambooth training always generate black samples [closed]

I'm using automatic1111's webui stable diffusion, and installed it's dreambooth extension, but when I train it with my images, the sample images it gave me are: one totally unrelated image, then after ...
10 views

### probability of being within a 2D grid cell

Consider two joint-normal gaussian variables A and B with known probability density. A and B form a point in 2D space. What is the probability that the sample point falls within a rectangular grid ...
24 views

### Plotting probabilities from multinomial regression output

I generated some data to visualize a multinomial logistic regression, where individuals choose a mode of transportation based on their income. I then set up a regression and predicted the ...
1 vote
7 views

### Partial autocorrelation significant at regular lag distance

I am trying to forecast inflation with a simple AR model. I took the natural logarithm of the CPI and subtracted the 12th lag, thus obtaining a measure of inflation. The PACF is significant at the ...
• 53
1 vote
19 views

### Reliability of yes or no questionnaire

I have a questionnaire of 15 questions with "yes" or "no" responses distributed to 20 participants. It will be used as an index measure of a variable. How do I measure the ...
15 views

• 133
26 views

### How to use validation set in the time series while doing a naive forecast?

I need to do a naive time series forecasting as a benchmark. Therefore, I should split my dataset into train, validation, and test sets. If I divide the the dataset into train and test sets, the code ...
• 267
1 vote
19 views

### Distribute feature importance to the components of the features in a PCA regression?

I read some interesting speculation over on the Data Science Stack. The setup is that there are multiple correlated features in a regression problem, and the goal is to determine feature importance. ...
• 43.5k
358 views

### Why is the Tukey's IQR not used in the R program?

I was writing an R Markdown for calculating measures of spread and was surprised to find that the IQR function does not use the IQR calculation I am used to using, ...
• 2,640
17 views

### Why sample size calculation for ratio-based metric doesn't consider the standard deviation of the ratio

When calculating sample size for ratio-based metrics like CTR or Purchase Rate, it appears that one doesn't need to consider the standard deviation of the ratio metrics. I tried calculators like https:...
• 201
31 views

### Survival Function vs Conditional Survival Function?

Consider the Survival Function: $$S(t) = P(T_1 > t) = 1 - F(t)$$ Where: $S(t)$ is the survival function, which gives the probability of surviving past time $t$. $T_1$ is the random variable ...
• 6,862
4 views

### Verifying Percentile and BCa Bootstrap assumptions and correct monotonic transformation of original data

Verifying Ordinary Non-Parametric Bootstrap and Bias-Corrected and Accelerated (Bca) Bootstrap Independent and Identically Distributed (i.i.d.) assumptions and correct Monotonic Transformation of ...
17 views

### What is the best way to compare adjusted survival outcomes between groups

I have a dataset of patients who all underwent one of three types of treatment. The disease they have can be graded on a scale of 1-4. The question I would like to answer is: Is there a difference ...
Suppose that for $\theta ∈ (0, 1)$, $X$ is a continuous random variable with density \$f_\theta(x) = \frac{3(1 − \theta)} {4\delta^3(\theta)} [\delta^2(\theta) − (x − \theta)^2]\mathbb{1}(|x − \theta| ≤...