Refers to the interface of statistics and computing; the use of algorithms and software for statistical purposes.

learn more… | top users | synonyms

0
votes
0answers
22 views

Fitting multiple logistic functions at once with pymc

I have read a similar post here Fitting logistic function with pymc but it seems there is a rule that I shouldn't ask question in someone else's post. My approach is to fit 10 logistic functions to ...
1
vote
1answer
77 views

Constructing one-ninth fraction of the $3^{5}$ design

I want to construct a $3^{5-2}$ design with $I=ABC$ and $I=CDE$ as generators. The complete defining relation for this design is: $I=ABC=CDE=ABC^{2}DE=ABD^{2}E^{2}$. This is a resolution III design ...
1
vote
1answer
43 views

How to make sense of 6mo worth of weight loss data?

-I have ~6mo of data that contains daily weight/caloric intake & #carbs/fats/proteins. I'm trying to figure out a way to make sense of the data. It's not a perfect experiment so there are other ...
0
votes
0answers
8 views

Need help using subset within lineplot.CI function in R [migrated]

I am a statistics and an R novice who is learning alot about both using RStudio. I have a imported a dataframe with the data in long form for mixed effects ANOVA on a longitudinal balanced study ...
0
votes
0answers
26 views

How to interpret the LDA output in R?

Basically, I have following LDA output (below). My question is how do I actually interpret it ? I could not find much resources on the web. Especially, what does "Group Means" really mean here ? I was ...
3
votes
3answers
57 views

Given two sets, how can I say statistically if they are similar/different

This is a very open ended question. Suppose I have two sets of data samples of the same form, say [item, rating]. Rating is a value on the interval [0,100] and item is a unique identifier given to a ...
1
vote
0answers
17 views

Condition number of covariance matrix

I am interested in generating a covariance matrix of dimension say 100. I managed to get a correlation matrix with finite condition number. To construct a covariance matrix I need to have standard ...
0
votes
1answer
47 views

Basic R script/package with lots of automated calculations [closed]

Does that exist? A basic R script or package that just needs the data, and it spits lots of “basic” statistics (like the mean, the median, quartiles, make a plot, a boxplot, a histogram, a cumulative ...
5
votes
1answer
56 views

Advice on sensitivity analysis for priors in Bayesian statistics

I'm not clear on how to perform sensitivity analysis on the priors. Many sites have different answers. One site indicates to perform three non-informative, weakly informative and known priors. Another ...
0
votes
0answers
13 views

What are the advantages of using a Neural Network to impute data?

What are the advantages and drawbacks of using neural network methods to impute data? Is the bias and total error any higher than other methods (e.g., median or mean method, nearest neighborhood, or ...
0
votes
1answer
84 views

What is SVM regression? Is it for regression or classification?

I'm trying to understand what is SVM regression. It's used for classification or regression? Can someone give an intuitive understanding of it?
0
votes
0answers
11 views

Levenberg-Marquardt adjustment

I understand that Levenberg-Marquardt adjustment is about adding $\lambda \times\; I$ to second derivative of the log likelihood function, where $I$ is the identity matrix $$-[l''(\theta | Y) - ...
0
votes
0answers
31 views

Project in Bayesian biometrics

I'm working on a project about specific bird species on an island in the Northern Atlantic sea. The data seem reliable and pretty detailed, and range from the 18th century, however their structure and ...
1
vote
0answers
19 views

Newton Raphson Algorithm: negative semi definiteness [duplicate]

I would like to minimise the function $l(\theta|Y)$. Given the Newton's method below $$\theta^{(t+1)} = \theta^{(t)} - \left[l''(\theta\;|\;Y)\right]^{-1} l'(\theta^{(t)}\; | Y)\quad t = 0,1,...$$ ...
1
vote
0answers
18 views

How to extract “average polyline” from a set of polylines [duplicate]

EDIT: As pointed, there is already a similar question "buried" inside a larger-scope one. I'll reproduce the relevant part here: If I have multiple recordings of the same routes are there any ...
0
votes
1answer
42 views

How to calculate the probability of winning an election?

I'm analyzing a survey data that contains the following 3 variables (questions): If the election was today who would you vote for in the following list? (A, B, C, D, or E)? Let's imagine the ...
0
votes
1answer
58 views

Probability of webpage accessed in a particular hour

I want to programatically calculate at which particular hours of a day the probability of a webpage hits(accessed) are high. Which statistic formula should I use to calculate the peak hours of the ...
0
votes
1answer
66 views

Computation of a binomial probability: nan result

I am computing binomial probabilities for many parameters. I am using the library scipy.stats: b = scipy.stats.binom(n,p) probability = b.pmf(k) I have noticed ...
1
vote
2answers
42 views

Sampling from low probability regions

I have a pdf that I need to sample from, but I'm having numerical issues and was hoping someone could provide some insight. My pdf is a product of gaussians $$ P(\theta |d ) = \prod_{i=1}^{N} C_{i} ...
2
votes
1answer
86 views

Statistics for Area under the ROC curve

I have a question regarding statistical evaluation of the AUC. In their paper (http://www.jstor.org/stable/2531595), DeLong et al. describe a method to evaluate AUC curves. (Another good explanation ...
1
vote
0answers
20 views

Statistical method to map a set of values to another

I am completely newbie to stats. And I want to know which statistical method would be applicable for following scenario. I have a bunch of sentences extracted from a text document. Each sentence has ...
1
vote
0answers
33 views

Finding the equation for a data set

I asked this question on StackOverflow and someone pointed for me to ask this here. Lets assume that I have 3 variables: x, y, z which are integers. I have 5000 values of each and I want to predict ...
1
vote
1answer
80 views

Why is the lower limit of my lower 95% confidence interval negative?

I'm conducting some research related to the use of patient data and quality of care. I'm generating a linear regression graph between phone bill size and customer population. Assume that the intercept ...
0
votes
0answers
22 views

Non linear maximization problem

I am not sure how I can solve this optimization problem. I have a (MATLAB) code which can solve this but only for very low dimensions, that is, low values of $n$ (around $n = 4$ or $5$), once $n$ ...
0
votes
0answers
28 views

Creating an index with objective and subjective variables

I have some objective and subjective variables. My aim is to create a statistical index which defines variables and interrelations of variables accurately. For instance, suppose that I am creating a ...
0
votes
0answers
33 views

Distance between nominal vectors: a review

I have a seemingly easy question which however is troubling me a bit. I have couples of vectors made up of nominal attributes. They can be of different length and sometimes some of the attributes in ...
1
vote
0answers
46 views

Tricks for a very fast implementation of Random Forest

I am implementing my own Random (regression) Forest algorithm and am looking for tricks to speed up the estimation of forests on large datasets. So far I have implemented three main tricks: 1) Use a ...
3
votes
1answer
49 views

How to split nodes in regression trees

I am looking for a comparison of different regression tree node splitting approaches within the random forest framework. I am looking at the trade-off between ensemble accuracy/reliability (holding ...
0
votes
0answers
16 views

Discretization of the split in random forest estimation

If the dataset I'm working with has too many independent variable dimensions, I may need to choose a proper subset of all possible locations in my feature vector to determine whether I am going to use ...
3
votes
0answers
49 views

Changepoint Analysis in R for Time Series Data

I'm new to R and statistics in general. My background is in Software Development, and I've tasked myself to solve a problem in a 3rd party application. This application is a Game, and I'd like to ...
0
votes
1answer
107 views

Calculating pointwise mutual information between two strings

I have a dataset consisting 5000 sentences. I need to calculate PMI between 3-gram and 5-grams in this dataset. For example: The 5-gram is: $x_1$$x_2$$x_3$$x_4$$x_5$ And the 3-gram is: ...
1
vote
1answer
120 views

Material on Structural Equation Modelling (SEM)

I've little background on SEM. Now I want to focus on its theoretical aspects like statistical model, model estimation and model evaluation. The seminal book on this topic is by Bollen: Structural ...
0
votes
0answers
29 views

Statistical Tests for comparing groups

I am a biologist and I have developed an algorithm that has the ability to identify and quantify fluorescent objects within the nucleus of a cell when imaged in a fixed state under a microscope. The ...
0
votes
1answer
43 views

Test to measure the significane of performance enhancement

I have 5 different computational tasks. I executed both tasks on two laptops named LA and LB. Out of 5 tasks, 4 tasks were computed in less time on LB, while 1 task took less time on LA. I want to ...
0
votes
1answer
29 views

Application “tuning” based on statistics: Lowest-Learning-Curve API for Java programmer?

I want to write an application, where users will have to choose between different "configurations", and I am looking for a way to statistically validate the "balance" of those "configurations", to ...
1
vote
1answer
71 views

IV estimator: efficient implementation?

I would like to implement (in R) an instrumental variable (IV) estimator, that takes the most general form (here not 2SLS or GMM!): $$ \beta_{IV} = (Z'X)^{-1}Z'Y $$ I could code this in the naive ...
0
votes
2answers
82 views

GA or ANN, and suggestions

I am working to approximate, to extrapolate rather, values of a function from a few known values. Here is what I have: Less than 100 known I/O pairs. A monotonously positive correlation.en Something ...
3
votes
1answer
281 views

How do I get the amplitude and phase for sine wave from lm() summary?

A simple sine curve could be written as $\text{amplitude}\cdot\sin(x+\text{phase})$. It can be also written in linear form as $a \cdot \sin(x) + b \cdot \cos(x)$. I run my analysis with R as: ...
0
votes
0answers
42 views

Thinning samples obtained using population MCMC methods

I am trying to use a Population Markov Chain Monte Carlo algorithm for parameter estimation in an ordinary differential equation model of gene regulation. The paper here gives a good summary of ...
2
votes
1answer
154 views

What is the time complexity of Lasso regression

What is the asymptotic time complexity of Lasso regression as either the number of rows or columns grows?
0
votes
2answers
131 views

Computational statistics book

Can anybody recommend me a good book on Computational Statistics? I am new to this subject so I am not sure how to be more specific.
1
vote
1answer
70 views

Translating R lme comand to mathematical equation

I would appreciate if someone could help me in translating the following R command into a mathematical equation: ...
0
votes
0answers
40 views

$\lambda$ in $\mathcal{L}_1$ penalized logistic regression and the likelihood on the training dataset

Define $J(w) = -l({w},\mathcal{D})+\lambda||{w}||_2^2$, then is it true that $l(\hat{{w}},\mathcal{D}_{train})$ always increase as we increase $\lambda$?
1
vote
1answer
108 views

Computing mutual information

I have a problem when computing the mutual information between two variables. Let's consider the following table: ...
2
votes
0answers
100 views

Data Correlation for Predictive Basketball Model

Background Information: (scroll for question) Attempting to find correlation between the average number of fouls committed by each basketball team in a game and the referees calling the game. Such a ...
0
votes
0answers
25 views

Proving the Accept-Reject Algorithm

Prove the following is equivalent to the Accept - Reject (AR) algorithm. Generate $X \sim g$; Generate $U|X = x \sim U_{[0; Mg(x)]}$; Accept $Y = X$ if $U \le f(x)$ Return to 1. otherwise. ...
1
vote
1answer
49 views

Balanced cross validation

I understand what is K-fold cross validation, but what does balanced folds mean? I thought k-fold cross validation is balanced. What are the differences between the two?
4
votes
3answers
121 views

How to measure student skill level based on a set of questions answered at different points in time and of different difficulties levels?

I am working on an e-learning system with a friend for our final year (Computer Science) project which is part of the under-graduate programs mandatory 'courses'. I have a question about making ...
0
votes
1answer
66 views

How to simulate data for those distributions which are not defined in MATLAB [closed]

Suppose there is any distribution whose parameter values are known. So how to simulate data in this case?
0
votes
1answer
106 views

Comparing two probabilities from the same normal distribution

have a normal distribution. I would like to compare two input probabilities from this population to measure how "similar" they are. Everything is subjective but I wanted to be able to say that $x$ is ...