All Questions
203,299
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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
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0
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10
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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.
...
- 11
0
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0
answers
8
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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
0
answers
30
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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
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15
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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
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6
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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 ...
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0
answers
11
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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 <...
- 11
1
vote
1
answer
29
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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
0
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0
answers
18
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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
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0
answers
6
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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
0
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0
answers
5
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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 ...
- 1
0
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0
answers
19
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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
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votes
1
answer
31
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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
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0
answers
14
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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 ...
- 81
2
votes
1
answer
41
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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:
- 485
0
votes
1
answer
13
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Econometrics Random Effect moddel
In R, I wrote the following lines of code - I need to "translate it" into a mathematical expression :
...
0
votes
1
answer
30
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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 ...
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0
answers
9
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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
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0
answers
32
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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
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0
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22
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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
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0
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33
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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
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0
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11
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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?
- 1
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1
answer
25
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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
0
votes
0
answers
18
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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 ...
- 1
0
votes
0
answers
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. ...
- 1
0
votes
1
answer
19
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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
0
votes
0
answers
13
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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
...
- 101
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0
answers
12
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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 ...
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0
answers
10
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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 ...
0
votes
1
answer
24
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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
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0
answers
7
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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
1
answer
19
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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 ...
- 11
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0
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15
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How to calculate the likelihood for new component? in Gibbs sampling for DPMM
I'm using Gibbs sampling for the posterior inference of Dirichlet Process Mixture Model (DPMM). During the sampling process for $c$, the category assignment variables, we have
$$P(c_i=c|c_{-i},y_i,\...
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1
vote
1
answer
16
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Should we reinsert trend after doing forecast using detrended data?
Basically, when we detrend a signal, we detect and remove a linear component of that signal. This produces a stationary version of that signal. And we can use various forecasting algorithms to ...
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votes
2
answers
32
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How to isolate the impact of one variable via regression?
I know the dependent variable $Y$ is a function of $X$ and $Z$, while $X$ and $Z$ are orthogonal. I want to quantify the impact of $X$ on $Y$, but the problem is that $X$ is unobservable to me. Is it ...
1
vote
1
answer
15
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How testing (new data points) works in graph neural network
In machine learning, data is divided into train and test splits. The machine learns weights using training data and we can utilize weights to predict test data.
Similarly, we are also learning weights ...
0
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0
answers
18
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Probability of flipping a coin 20 times and, given that the number of heads is twice or more the number of tails, obtaining an odd number of heads [closed]
First of all, I have obtained using the binomial distribution that the probability of obtaining twice or more heads than tails is $0.0577$ (value which corresponds with the solution of the textbook). ...
- 101
0
votes
0
answers
9
views
How do I make sklearn.ensemble.GradientBoostingRegressor non-random? [closed]
I am experimenting with sklearn.ensemble.GradientBoostingRegressor and finding that my results are sensitive to the parameter "random_state". I understand that this learning algorithm can be ...
- 656
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votes
0
answers
8
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how to compare CFA models with correlated disturbances?
using lavaan in R, I am fitting a 4-factor models using confirmatory factor analysis (based on a "validated" scale). As the original authors did, I let 5 residual errors (disturbances) of ...
- 1
1
vote
3
answers
56
views
Should the formula for test statistic have an absolute value?
I have been given a formula for calculating a t test statistic as
$$t_{n-1} = \frac{ \bar{x}- \mu_0}{\frac{S}{\sqrt{n}}} $$
Where $\bar{x}$ is the sample mean, $\mu_0$ is the hypothetical true mean, $...
- 579
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votes
1
answer
26
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Interpretation and application of PCA - positive factor patterns for first component for all variables
I am attempting to reduce the number of variables in a dataset for regression purposes and I suspect that many of the variables are correlated. Hence, I attempt a PCA, which I must admit I'm very new ...
- 3
3
votes
5
answers
224
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Why are $X \sim U(-1,1)$ and $Y=X^2$ dependent?
Suppose we have two continuous random variables $X \sim U(-1,1)$ and $Y=X^2$. I don't understand why they are dependent.
$$E[X] = 0$$
$$E[Y] = \int_{-1}^{1} x^2 dx = 2/3$$
$$E[XY] = \int_{-1}^{1} x^3 ...
- 133
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0
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26
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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
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0
answers
19
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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
9
votes
2
answers
358
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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
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0
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17
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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
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1
answer
31
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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
0
votes
0
answers
4
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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 ...
0
votes
1
answer
17
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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 ...
- 11
2
votes
1
answer
64
views
A proof for existence of MLE
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| ≤...
- 221