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4 views

Determining sample size for chi squared

I'm currently writing a project proposal in which i've been told i need to estimate the sample size i require. Im planning to look at the effect of culture time (split into three groups) on IVF ...
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3 views

How to know how did voters changed their mind since last elections through linear regression?

I have a dataset of precincts and results of parties on different elections (let's focus on two : 2008). After reading this article I really wanted to use linear regression to answer the question : ...
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Conditional heteroscedasticity for the tobit model in Layman's terms

I have been using the crch package for modelling censored data with the tobit model. I noticed early on that the errors (by far) are not normally distributed by ...
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0answers
2 views

Does negative Z score in Cochran-Armitage test implies the presence of an increasing trend?

Given the p-value is less than 0.05 does negative Z score in two-sided Cochran-Armitage test implies the presence of an increasing trend?
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2 views

Croston's Method (forecast)

I ran Croston's Method on this data(Sales) with h=3 ...
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0answers
2 views

how to choose the number of patches in sub-region classification before appling CNN?

I'm currently working on image classification, i want to divide the input image into sub-regions(patches) and apply a deep convolutional neural network (CNN) to train and classify each patch ...
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2 views

Sensitivity analysis of an equation in R language

I have the equation, Y = A*B*C/(D*E) Where A, B, C, D and E are the certain parameters of 1000 samples (say groundwater samples). ...
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0answers
2 views

How can I accomodate the forecast series to separately fit and predict workdays and weekends?

I'm using the forecast R package. I have the same dilemma as How to forecast daily time series with weekends and holidays?. I understand that the answers consensus ...
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0answers
10 views

Hard time understanding the parameters of a prediction interval

I stumpled upon the definition of a prediction interval from https://www.statisticshowto.datasciencecentral.com/prediction-interval/ In my setup I have a type of tree-based regression model with non-...
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1answer
7 views

Finding joint distribution of sum of independent Poisson random variables and calculating probabilities

My textbook, Introduction to Probability, by Blitzstein and Hwang, provides the following problem: Let $X = V + W$ and $Y = V + Z$ where $V$, $W$, and $Z$ are independent $\text{Pois}(\lambda)$ ...
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3 views

Asymptotic distribution of intraclass correlation

Consider the random effects ANOVA model below (notation based on Snijders and Bosker, 1999), where $j$ represents a group and $i$ an individual: $$ Y_{ij} = \mu + U_j + R_{ij}, \qquad var(Y_{ij}) = \...
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6 views

Clustering using histograms

I need to find clusters in a very large amount of data (>2M data points), and I was looking for ways to speed up the usual algorithms, i.e. k-Means, DBSCAN, ... Is there any major issue, especially ...
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5 views

Finding the maximum and minimum variance of the sum of two Bernoulli events?

You are guessing the contents of two envelopes. Let Ui be the event that you guess correctly. Your probability of guessing correctly for each envelope is P(U1) = P(U2) = 3/4. U1 and U2 may or may not ...
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0answers
10 views

SPSS and Linear Mixed Models

I hope you would be able to help me! I am working on a LMM in SPSS right now and I've gotten to the point where I don't really know what to do. I am looking into comfort (so that is my DV, measured ...
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0answers
7 views

How can I calculate principal components scores in a compositional data PCA?

I hope someone can help. Please let me know if my question is not clear. I have compositional data, where there are three variables which sum to 100% for each row, something like this: ...
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5 views

Statistical test for testing if test set is sampled from same domain as training using occurence of certain features

I have text samples pre-split in training / test for binary sentiment classification. I have a suspicion that the test set was sampled from a different domain than the training set. There are several ...
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0answers
7 views

Is having too many comparisons a valid reason to increase FDR threshold level?

To briefly summarize, I have a bootstrapped data set that needs to be corrected for multiple comparisons. The figure below provides a snapshot of one set of the data. The x-axis is in bins of 60ms. ...
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0answers
6 views

Subtract column values in python [on hold]

I have columns 'Longitude', 'Lattitude' and 'Battery' in my dataframe. I want to define a function if the difference between alternate battery value is more than a threshold, it should return 2 ...
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0answers
10 views

the convergence speed for a Markov chain

For a metropolis hastings algorithm, suppose that the stationary distribution is defined as the Gibbs Boltzmann distribution $\pi_T(x)= \frac{1}{Z_T}e^{-\frac{V(x)}{T} }$ where $Z_T = \sum_{y\in V} e^{...
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0answers
4 views

Variance Inflation Factor on many variables

I have a good amount of variables, where some/most of them are highly correlated. Like roughly 80 variables, and then maybe 50 are correlated in groups. So 20 of the 50 are highly correlated, and the ...
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1answer
15 views

Support of a function

What is the support of some function $F$ and why do we care about it? Is it of major significance for distribution functions?
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0answers
5 views

extracting seasonality - using fourier transform vs. learning the coefficients of fourier terms

I'm following hydman's advice for using fourier terms when fitting a linear regression model to the taylor time-series (with the very long seasonality of 336). My ...
1
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1answer
14 views

Inference problem, having issues translating problem from words into probabilistic terms

This is the question: There are particular readers for swipe cards, Under normal operating conditions, there is a small probability of 0.02 that swiping a card fails to open the entrance - some of ...
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0answers
2 views

Attrition from HIV Care And Predictors Of Attrition From Care Among HIV Infected Adults Receiving ART,this my research problem [on hold]

can i conduct/estimate/ an incidence rate in case control study and also is it possible to analysis survival from case control study?..as my knowledge incidence rate will be best ok with cohort study,,...
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0answers
6 views

Which model is best using the hettest for heteroscedasticity test?

I have calculated hettest using STATA and i have found two models have no Heteroscedasticity problem. but i can not identify which one is the best model for my data. can you please help me out? I ...
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2answers
29 views

Clarification - Random Variable

I'm working on Introduction to Probability Theory by Joseph Blitzstein. Definition 3.2.1(Discrete random variable). A random variable $X$ is said to be discrete if there is a finite list of values $...
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0answers
7 views

R hypothesis testing (non parametric)

Working with the Golub dataset, I am attempting to use the Wilcoxon two-sample test to find the genes that have a higher mean expression value in the AML group as compared to the ALL group. What is ...
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0answers
12 views

ARIMA forecast for upcoming 2 days

I am trying to forecast the battery charge for the next 2 days. I have data for 3 days with 5 mins interval. I have tried the below code: import statsmodels.api as sm arima_mod = sm.tsa.ARIMA(...
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0answers
3 views

about PMI(pointwise mutual information) independence

as picture shows it says A, B are independent which means P(A,B) = P(A)P(B). then isn't pmi always 0? because log1 = 0? what am i assuming wrong here?
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15 views

What are the odds [duplicate]

What are the odds Ive met my other half? Thing is I already know I have with this undeniable experience we had when our souls actually collided together as we were one. I just want to know what ...
1
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1answer
8 views

Regression with ranked and truncated dependent variable

I'm struggling to find a model that will best fit this data. The dependent variable is the ranking of a observation based on how many votes it received based of a list of choices (number of votes is ...
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0answers
6 views

How to partition a correlation matrix into two extreme groups?

I have a correlation matrix of 40 random variables: $C_{ij}$, $1 \leq i,j \leq 40$ I want to partition the 40 variables into two groups (of 20 each) such that the average correlation differs by most ...
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1answer
6 views

Measuring variation explained in community matrix using both geographic distance and and environmental variables

So I have this dataset where I have species community data from a variety of sites. I’m trying to explain what are the factors that drive the variation in these data. For each site, I have a ...
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0answers
9 views

Calculating Confidence Intervals SPSS [on hold]

Using the "Example Dataset," complete the following: Based on a normal distribution curve, calculate the probability of an individual being 60 years or older in this population. SPSS formulas ...
3
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1answer
13 views

Difference between Multivariate Regression vs Iterative Regression on Residuals

Suppose one has an n × 2 matrix X (the independent variables) and a n × 1 vector y (the dependent variable). In a standard multiple linear regression setting, we solve for the 2 × 1 beta vector that ...
0
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1answer
12 views

can i use logistic regression in discrete feature types

can i use logistic regression in discrete feature types problem. Since recently i knew that the expression for logistic regression is derived from guassian naive bayes and we can use guassian naive ...
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0answers
16 views

Can knn be used for multivariate multiple regression?

I am working with MLB data with around 15000 observations for seasonal player stat. The data frame's structure looks like this (I'm making up the stats): ...
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2answers
28 views

What test should i use to prove A is better than B [on hold]

I have sets of data that have number of goods produced by 2 machines, A & B for 2 months. Each machines has two numbers that is plan value and actual value. I'm not really familiar with hypothesis ...
2
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2answers
27 views

Is it appropriate use the Binomial Theorem to analyze the problem of rolling dice?

In mathematics, the multinomial theorem describes how to expand a power of a sum in terms of powers of the terms in that sum. It is the generalization of the binomial theorem from binomials to ...
0
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1answer
19 views

Looking for an statistical method [on hold]

A large data containing the amount of SO2 concentration from the exhaust of cars in the USA is available. Let's say I am a car company agent and the USA government asked me to come up with a "maximum ...
0
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1answer
22 views

Can anyone hep me to find the probability of the following question please? [on hold]

The organizers of a banquet at a restaurant have ordered 10 place settings, but they have invited 13 people. Past experience indicates that 15% of the people who are invited independently decide not ...
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0answers
8 views

Bounds on dependent truncated random variable with given mean and variance

I have two random variables $X$ and $Y$ with given (mean, variance) as $(\mu_{X}, \sigma_{X})$ and $(\mu_{Y}, \sigma_{Y})$, respectively. These random variables have their truncated counterparts: $tr(...
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0answers
12 views

Bayesian update vs optimization in multivariate case

Say I have a multivariate normal vector $r$~$N(\mu , \Sigma )$ and I observe that $ y \equiv Pr + \epsilon = Q$ where $P$ is a matrix and $Q$ a vector and $\epsilon$~$N(0 , \Omega )$. Now I ...
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0answers
8 views

Convert median absolute deviation (MAD) to SD for log-normal distribution

How do I convert the $\text{MAD}$ (median absolute deviation from the median) of data that is drawn from a log-normal distribution to the standard deviation of a log-normal distribution? To clarify, ...
1
vote
1answer
17 views

ARIMA forecast confidence intervals

Can someone explain how confidence intervals for ARIMA forecasts are derived? I can't seem to find any good explanation of it. From what I've read it seems like because an ARIMA process can be ...
0
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0answers
15 views

Does Neural Net with Softmax activation function violate the IIA assumption?

Multinomial logistic regression have assume the IIA (independence of irrelevant alternatives (IIA), IIA assumption: difference logit and probit); but I'm wondering if using Neural network in which the ...
-1
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0answers
9 views

Why do I get a different p-value when using summary(table(DF)) vs. chisq.test(table(DF))? [on hold]

I have a dataframe (DF) that consists of 2 variables with ~43500 observations. The first variable is a numeric (1-6), the other is a factor with 2 levels (PRE & POST). Why does R give a different ...
0
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0answers
10 views

Calculating a baseline probability model for images

I'm a newbie to statistics, so I apologize if this question is trivial. I'm trying to build a distribution that can predict a specific set of images. But first, I need a baseline - so, I decided to ...
0
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0answers
8 views

WoE optimal binning algorithm [on hold]

I'm trying to translate this thing into a working algorithm. The paper here describes the algorithm implemented in MatLab. There is an alleged python translation here. but I never managed, or saw ...
0
votes
1answer
12 views

What significance test should I use for my scenario? [on hold]

I am comparing the blitz frequency for a football team by down (1,2,3) How can I determine if the frequency for blitzing on first down is significant compared second and third down...etc. I have the ...

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