# All Questions

14 views

### Deciding Minbucket size in R

What is the criteria for selecting minbucket size in CART in R? Is there any formula for choosing this, based on the number of observations?
30 views

### Clustering in Industry - Why only k-means? [on hold]

How successful is clustering in industry as opposed to academics? More specifically, it seems like clustering algorithms geared towards mixed data type data sets aren't implemented by the common ...
21 views

### Convert object output in console to string in R [on hold]

Consider the following R program ...
33 views

### How can I know how 'descriptive' my data is?

I'm an undergrad learning about Statistical/Machine Learning and I've implemented and fitted some models now using methods such as Neural Networks and SVM. I've noticed that when testing some datasets ...
13 views

### Can binary svm have labels 1 and 26(any number but not 0,-1 or 2)? [duplicate]

I trained binary svm with lables 1 and 26. but while classification it returned a label of 1 and 2 which i have not mentioned during training. i thought it would return 1 or 26.
39 views

### all dependent and independent variables are categorical

I have 2 categorical dependent variables and 1 categorical independent variable. By which regression model I can calculate odds ratio? For example the dependent variables are the cancer stages (0-4),...
16 views

### Confidence and Prediction Intervals for Multiple Linear Regression Model

I am looking for a derivation of confidence and prediction intervals for a multiple linear regression model. I have seen that for a given vector of predictors $(x^*)$ and $X$ denoting the design ...
33 views

### What happens when GLM (in R) is given 2 correlated variables?

I have this data where I chose the feature as - Amount of credit and the variable to be predicted is the Credit Rating (good or bad). I ran the logistic regression and I got an accuracy of around 67%...
14 views

### Extreme value theory: GPD larger expected value than average

We're using extreme value theory to model tail risks on our portfolio. After we choose the threshold, we fit generalized Pareto distribution to our data over the threshold. The expected value of GPD ...
85 views

### Basic Hypothesis Testing

I'm having trouble with a basic hypothesis testing question that I just thought of. The question is the following: suppose you know that a certain lawnmower manufacturing company (called Company A) ...
37 views

### Why does Geoffrey Hinton say in his Coursera course that gradient magnitudes can vary widley when training Neural Networks?

I was watching his coursera course video on RMSProp and he said in a paraphrase: Gradients magnitude vary widely. I was wondering, why is it that they vary widely? I had a guess but wanted to ...
9 views

### Odds ratio in multivariate GLM

How to calculate odds ratio in multivariate GLM? I selected parameter estimation in option but the outcome didn't show EXP(B).
83 views

### The proof of shrinking coefficients using ridge regression through “spectral decomposition”

I have understood how ridge regression shrinks coefficients towards zero geometrically. Moreover I know how to prove that in the special "Orthonormal Case," but I am confused how that works in the ...
16 views

### Relationship Between Percentile and Confidence Interval (On a Mean)

This question came up at work when someone asked me what the relationship was between a percentile and a confidence interval, and I had a very hard time articulating my thoughts. The context was a ...
42 views

### R-Monte Carlo simulations for ARMA model [on hold]

I have 5 years of daily price data of an asset for which I have fitted an ARMA model. I want to generate 10000 simulations for next 6 months using the last available value for the asset as starting ...
57 views

### Suggestions for appropriate regression models? [on hold]

The image is like a larger version of the one posted, but not as clear. I am trying to find a model that can fit to that pattern so that I can identify when there is a break in the pattern. I am ...
13 views

### How can I write an R script to check for straight-lining; i.e., whether, for any given row, all values in a set of columns have the same value [migrated]

I would like to create a dichotomous variable that tells me whether a participant gave the same response to each of 10 questions. Each row is a participant and I want to write a simple script to ...
81 views

### What are multi-variable calculus pre-requisite for Machine Learning

I wanted to complete calculus pre-requisites for machine learning class. I am doing an online course of multi-variable calculus. Can someone please suggest what lectures after Lecture 15 are relevant. ...
87 views

### What is the best way to detect repetition in xyz data for purposes of splitting data?

I'll use this picture to explain What I want to do is define some patterns as trained patterns. Then given data I want to be able to determine if the pattern exists in the dataset, and if it does ...
45 views

### Transforming observed Fisher information

Let $x_1$,$x_2$,....$x_n$ be a random sample from the exponential distribution with p.d.f.: $$f(x;\lambda)=\lambda e^{-\lambda x}\;\;\;x\geq0\;\;\;\lambda>0$$ The log-likelihood is: l(\lambda)=...
13 views

### Identify differentially expressed genes across genotypes

I have 40 different genotypes of rice. For each genotype, I have two replicates under control treatment and two replicates under drought treatment. We sequenced those samples and get read counts of ...
22 views

### Can you create a mixed effects General Additive Model?

I'm facing a challenge with how to apply a GAM to a dataset. I'm using network data, pretend for the sake of specificity, between individuals. I'm interesting in the relationship between team size and ...
21 views

### How do I test whether means are equal when I have summary stats for 2 samples from one population and for 1 sample from a second? [duplicate]

I think this is a "meta-analysis" situation. I've got 3 samples (from 3 studies); I've assumed that two are from population A (treatment A) and one is from population B (treatment B). I have the ...
44 views

### find groups given distance of each element with all the other ones

essentially, I have NxN matrices which contain the distance of each element of a a given matrix NxN against from all the other elements of such matrix. I want to find a way to comb through this ...
11 views

### Should I include the level variables along with the difference variables in the Error Correctional Model(ECM)?

I am running an ARDL model, I have both levels and difference variables. I know for sure that the difference variables should be included in the ECM but should I include the level variables as well?
17 views

### R - Weighted Euclidean distance function [on hold]

Does a Weighted Euclidean distance function already exists in R ?
24 views

### Correlation of 2 categorical variables in linear model

I have this dataframe with two categorical variables (Sex and Ethnicity (only Asian or European)) and I need to fit a linear model to estimate the weight of a fetus given the day of the echography and ...
37 views

### Perceptron trained on time series always predicting the same answer

Using the model from theano's tutorial (http://deeplearning.net/tutorial/mlp.html), I'm training a 3-layers perceptron with log returns over a very large dataset (~55,000 points). The output's layer ...
38 views

### Big difference of accuracy between C-SVC and nu-SVC using SVM

I'm currently dealing with an image classification problems. The objective is to classify the images to 4 classes, with 8000 images in the training set and 14000 images to predict. I'm using the SVM ...
151 views

### Is multicolinearity problem ignorable under this situation?

When I run the logistic regression, two independent variables have VIF values greater than 10 like 13 or so. Logistic regression is the one I will use to measure the overall change in the dependent ...
9 views

### Holt-Winters Damped Method in SAS?

Is there a way to implement the Holt-Winters Damped Method in SAS? In the documentation for PROC ESM it details how to use the Winters Additive and Multiplicative methods but no mention of also ...
34 views

### Hierarchical clustering with categorical variables

Can categorical variables be used in hierarchical clustering? I have heard only continuous variables are used, but have seen people discussing categorical variables may / may not be used as well. ...
24 views

### Variance of continuation-ratio logit estimator

I wanted to calculate the variance of continuation-ratio logit estimator that defined as $\hat{\theta}^+_j=\ln\frac{\pi_j}{\sum_{k=1}^{j-1}\pi_k}$, for $j=2,...,C$, where $C$ is number of categories. ...
28 views

### math statistics [on hold]

person a and person b both took the same test. person a got a score of 100 while person b got a score of 75. in order for a counselor to determine whether the difference between their scores was ...
31 views

### How do I avoid multiple t-tests (or is it ok to use multiple t tests here?)

I've searched around CV for a bit, and have not found a good answer as to what test to use instead of multiple t-tests in my particular situation. I am interested in comparing mean size (of fish) ...
18 views

### Grouped monthly sample sizes

This will be really simple, but I'm having a hard time figuring out how to Google this. Let's say we have 12 months of trailing data on something like "Calls per month," and that data is on the low ...
32 views

### Linear Mixed Effects Models - combining coefficients

Suppose I have a sample of height data for a population with sex and region identifiers. Now, suppose I estimated the linear mixed model against a variable $x$. I'm using the ...
10 views

### Parametric versus nonparametric ROC analysis

SPSS offers two ways to estimate Area Under the Curve (AUC) and its standard error, that is nonparametricly using trapezoidal rule or parametrically using binegative exponential distribution. I have ...
15 views

### Sales Regression Analysis: Control for individual sales people

I am doing analysis on sales person behavior. I am measuring what effect certain sales behaviors have on revenue. An example of measured behaviours might be: number of phone dials, time on the phone, ...
31 views

### Fractional dependent variable: Why not use Poisson regression?

In many settings, we are interested in estimating a model with a fractional dependent variable. For example, Papke & Wooldridge (1996) http://faculty.smu.edu/millimet/classes/eco6375/papers/papke%...
14 views

### How to separate two classes when the features values predicting them are so similar ?

What should be my approach. I got 13 principal components from 21 numerical features. The 13 features have a gaussian distribution. The plot below is between the top two components. Should I clean the ...
16 views

### how to plot a binomial glmer with two binomial predictors?

I have a response variable called Percieved Personality (responsible-sympathetic) predicted by Birth Order (Firstborn-Laterborn) interacting with Sex (Male-Female), with 2 random effects. I just want ...
73 views

### Why does the post-hoc results in R differs the post-hoc results in SPSS?

I have run the same two-way Repeated Measure ANOVA in R and in SPSS. Following that I ran a Fisher's Least Significant Difference (LSD). R script ...
505 views

### Can I ignore multicolinearity problem if all the regression coefficients are highly significant? [duplicate]

Can I ignore multicolinearity problem if all the regression coefficients are highly significant? My data is large enough (i.e. I have several regression models where each of the data points for them ...
28 views

### Cheminformatics in R v Python [on hold]

I have a process that will produce Cheminformatics models"CM" in R. The process is designed to produce the optimal subspace for a given dataset. It looks like Python will run faster with large ...
39 views

### Normalise X/Y coordinates to stop jitter

Disclaimer: I am a programmer by trade, not a statistician, so please cater to my ignorance and I apologize now if I make any incorrect assumptions Please consider the following problem: I am using ...