# All Questions

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### Granger Causality: Alternative Hypothesis for VAR

I know that if ALL the coefficients on the lagged values of, say, $y_2$ are $0$ in the equation for $y_1$, then $y_2$ fails to Granger cause $y_1$. Therefore, our null hypothesis for Granger ...
8 views

### Wilcoxon signed-rank test null hypothesis statement

I performed a one-sided Wilcoxon signed-rank (WSR) test. I had a matched pair of continuous random variables, say $X_1, X_2, ..., X_n$ and $Y_1, Y_2, ..., Y_n$. For my system, it is safe to assume ...
4 views

### Cross entropy for image segmentation

I'm running a FCN in Keras that uses the binary cross-entropy as the loss function. However, im not sure how the losses are accumulated. I know that the loss gets applied at the pixel level, but then ...
9 views

### Retention problem - we have too categories of customer - CPro and Hobbyist - how retention bad retention explain the loss for business [on hold]

I have these four data facts. please help me to understand the underlying data retention problem and solution. Qualitative survey results
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### Does my hypothesis fit my regression model?

Suppose I have the following model $y_i=\alpha+\beta_1*Revenue_i+\beta_2*IFRS15+\beta_3*Revenue*IFRS15+\beta_4...$ where Y = stock return, Revenue = actual revenue and IFRS 15 is dummy equal to 1 if ...
4 views

### Improving supervised learning for question text comprehension when there is no obvious answers

I'm trying to determine how to answer question from text with supervised learning. This used to work quite well when every questions had answers. Here is the head of dataset we used with the sentence ...
3 views

### Detect cyclic patterns in stream of characters with random noise

I am looking for an algorithm which can detect cyclic pattern in streams of characters which have random noise embedded in them. An example of cyclic pattern with a set of characters a - m for a ...
9 views

### Machine learning: 'train_test_split' function in scikit-learn

I am a beginner in machine learning, and I hope someone can help me. In Python's 'scikit-learn' library, the function 'train_test_split' splits the dataset into training and test sets. This is done ...
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### Will CDF and closed-form Quantile functions give same estimated parameters for a given distribution? [on hold]

Given distributions with closed-form quantile functions, since distributions are equivalently described by CDF's or Quantile Functions will we get the same parameter estimates from either form of a ...
19 views

### Logistic Regression Z-value

In logistic regression, when we look at Z-values or p-values, are we making an assumption that statistics or coefficients of a predictor follows normal distribution? Null Hypothesis is Coeficient of ...
7 views

### Multilevel Model Application / Specification

I have some multilevel-data-structure, where I want to regress top 10 music chart listings (dependent variables: downloads and rank) on some song characteristics (Xi). The problem for me now comes ...
10 views

### Moment generating function of a Weibull distribution [on hold]

I am trying to evaluate the moment generating function of a Weibull distribution with shape parameter $\tau>1$, I know that in this case it corresponds to a light tailed distribution. Basically I ...
6 views

### Is a three-level multilevel model appropriate for my research question?

for a study that is currently in the planning stage we are considering what kind of model would be most appropriate. We are interested in the interactive effect of a drug (vs. placebo) and hormone ...
4 views

### Standard error of coefficient in moving average model

I'm working with an asymmetric moving average model and I want to interpret the standard error of the coefficients in a similar model: I'm confused about what the standard error of a coefficient ...
23 views

### P value equal to 0.000 in every test: how is it possible?

I have 8 variables for which I have to examine whether they have a normal distribution or not. There are 270 observations for each variable. I've run a normality test on SPSS for each variable and all ...
17 views

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### clustering VS supervised classification, in the case of very small database

I'm trying to classify/cluster subjects according to 4 features in two classes: healthy and sick. Two things to know: I know the labels/classes of each subject + I only have 40 subjects (in total: ...
4 views

### How do you calculate a new scale from two given variables and then find out the cronbach-alpha?

The question concerns two variables with scores from a personality test, Ptest1 and Ptest2 with values from 60 participants from each variable. So how I can convert these two variables into a new ...
5 views

### Downsampling features: how to select the most optimal features to recapitulate clustering

I've performed single cell analysis in which each gene represents a feature to cluster upon; there are about 20,000 genes expressed across all the cells in the dataset. I use the top 1500 or so ...
8 views

### Is it possible to derive joint probabilities from marginals with assumptions about the conditionals?

I understand the title is too generic. I tried to look for similar questions and although there were a few that were seemingly about the same issue, either they provided answers in the negative or had ...
12 views

### State-of-the-art performance on CNN?

could you guys point me in the right direction to where I can find papers or information about the state-of-the-art performance for the CNN prediction (feed-forward) algorithms? I'm currently ...
18 views

### finding the top 2.5 % of my dataset [duplicate]

I am trying to find the top 2.5% of my data set. In other words, do a 97.5 confidence. The reason is I want to get rid of the top 2.5 % from my data set. I ordered my data from smallest to biggest ...
5 views

### Unsupervised Text Clustering Project: How to get started?

I work for a manufacturing company where robust databases and data integrity have not always been a priority. I have a very messy and finite list of 13,102 tool descriptions. I need to find out how ...
15 views

### Convergence in Distribution for i.i.d. data

Let $X_1,X_2,\ldots,X_n$ be i.i.d. RVs with $E(X_{i})=0$ and $V(X_{i})=\sigma^2$, $\sigma <\infty$.Is it possible to find real sequences $a_{n}$ and $b_{n}$ such that $a_{n}(\bar{X}^3_{n}-b_{n})$ ...
12 views

### Support Vector Machines: a beginner's question about the underlying math

I'm new to Support Vector Machines and I've been trying to get into the underlying math (instead of just using Scikit Learn or something like that). I understand the math behind it up to the point ...
6 views

### lp_solve starting basis

I'm working with some fairly large LP problems in R and running into very slow computation times. I'm using the 'lp_solve' solver R wrapper ( through lpSolve and lpSolveAPI packages ), and found the ...
12 views

### Assigning scalar values for PID for order in Neural Network

I have built a neural network using Windows Processes. I started off with only two features, the file path with parent process, and the file path with child process. I am slowly adding features for ...
8 views

### Couldn't make residual plot or qqplot using lapply to a list of residuals extracted from the lme [on hold]

I ran linear mixed model for multiple response variables using the R package, nlme. ...
14 views

### K-means Figuring out which label is which [duplicate]

So after k-means has assigned labels to each data-point. I want to map these labels to the closest pre-defined labels. I have 6 types of pre-defined labels on all of my observations. So the data ...
23 views

### Complex Venn Diagams [on hold]

I cant seem to move further with this Venn Diagram, can someone help me identify what I am doing wrong. The explanation is a follows: A group of 138 people: 39 had at least one tattoo 92 had ...
13 views

### How can One caluclate the p-value in shapiro wilk test?

I am trying to understand how shapiro-wilk test function. So far, I have come accross the following links: How are the values in the Shapiro Wilk weight table calculated? which explains how to ...
12 views

### multiple linear regression loop [on hold]

I have a data frame with five dependent variables (Yi) and 15 independent variables (Xi). my goal is to run a model that contains all possible combinations of Xi to explain each of the Yi. I think I ...
12 views

### How the variance in one set of variables accounted for a variance in another set of variables

I'm looking for a suggestion for ways/methods either in r or SPSS to answer how the variance in one set of variables could attribute for the variance in another set of variables. Here is the key ...
11 views

### What does the return value of loglik in R represent?

When I use the loglik function in R I get numbers like 1002, 1040, -4000, etc. What do these numbers represent? I was looking into maximum likelihood and it's logarithmic counterpart and I understand ...
36 views

### Logistic Regression or Cox regression?

I have a dataset for gym memberships over 5 years. I'm trying to predict what is causing people to cancel their policies. Variables I have include age, gender, income, locations... all demographical. ...
16 views

### Can I normalise data with (x-min)/(max+min) instead of (x-min)/(max-min) ? What will be the difference between the two? [on hold]

I want to understand these two methods. I know the second one is a standard one. Can I use the first for the same purpose? Please give reasons. Also, what are other ways to normalise data? Some ...
19 views

### does including “neighborhood income” as a feature increase or decrease bias (in the discriminatory, cultural sense)?

This is a question about reducing bias in models, in the cultural sense of unfair discrimination. I'm aware that adding features to a model will tend to decrease its statistical bias. The models I'm ...
6 views

### Plotting pairwise comparisons with emmeans? [on hold]

Is there a way to make plots with emmeans (precious lsmeans, while including the pairwise contrast assigned with ...
12 views

### Does Min-max scaling lead to information loss in time series or transaction data?

Given I have the following dataset and the data is transactional is nature. ...
6 views

### Using K-Means to cluster vectorized user reviews

I have a dataset of user written reviews. What I would like to do is to cluster similar reviews together. I have already trained a word2vec model on vocabulary of 50000 words, and I have updated my ...
13 views

### Sample or Population Statistics For 6 Months Worth of Data [on hold]

I have a 2 years worth of Monthly adjusted data. From that I am taking past 6 months of data to calculate mean and standard deviation. My Six months worth data looks like this, ...
4 views

### Standard deviation of standard deviation of autocorrelated timeseries

I'm trying to get an estimate of the error in my sample standard deviation (not a statistician at all, hope I'm using correct terminology). The timeseries is normally distributed and follows an AR1 ...
7 views

### For my data, should I use a Kruskal Wallis or one-way ANOVA test?

I read through some literature online and did some investigating on my data and the type of scales my data represents. In my data set, I have my independent variable called ASA status (this is a ...
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### Double Mediation?

can anyone help me with what this R (package lavaan) syntax? I got a question: Is it correct that a kind of nested multiple mediation is tested with this code (X = "predictor", XM1 = "predictor 2" in "...
19 views

### How I can work with data set contains both numerical and non-numerical features? [duplicate]

I have a dataset contains both numerical and non-numerical columns. I want to use PCA, is there any way to handle both?
12 views

### Dealing with many NA's in very large datasets for Lasso

I have a few very large and quite "dirty" datasets. Primarily, there are lots of NA's. Because the datasets are so large I would like to use LASSO, to aid me with variable selection. If I would ...