0
votes
0answers
2 views

How can I calculate a confidence interval for true mean of one set being higher than another, based on samples from each?

I have two sets A and B each containing N elements and want to show that the true mean of A is less than that of B with certain degree of confidence. (Specifically, the sets represents items of "yes" ...
0
votes
0answers
7 views

What is $\bar\mu_n$?

Am I right in thinking that it is the average of the sum of $n$ different populations means? Here it is used in the context that confused me. It's the Chebychev WLLN, apparently. "If $x_i, i = 1, ...
0
votes
0answers
6 views

Multivariate normality plots

To check multivariate normality, which is the best plot - a chi square qq plot for the entire set of variables or as many qqplots as the number of variables?
1
vote
1answer
7 views

Conceptual questions on Entropy and estimation

Learning Informative Statistics: A Nonparametric Approach paper presents an approach to parameter estimation by entropy minimization. There are other related works "Minimum-entropy estimation in ...
0
votes
0answers
10 views

Understanding ANOVA formula in R and choosing the most appropriate model

I am new to R (and by extension statistics), and am having a tough time in making sense of this repeated measures ANOVA formula, please bear with me. I think I understand what the formula implies, but ...
0
votes
0answers
8 views

Understanding Regression vs. Means/Median Results

I am having a little difficulty understanding my results - could someone help me understand how to interpret, and if my process is sensible? Here is an example of what I am doing I am trying to ...
0
votes
0answers
7 views

Iinterpretation of coefficients of multiple comparisons in a logistic regression model

I'm confused about how to interpret coefficients in relation to the reference categories. I have two variables, A and M. A is a 3-level variable and M is a 4-level variable. The reference category for ...
1
vote
1answer
14 views

Joint density of first r order statistics

Let $X_i \sim^{iid} F$ for $i=1,...,n$, where $F$ is a continuous distribution. I want to find the pdf for $X_{(1)},X_{(2)},..., X_{(r)}$, with $r\leq n$. We know that $f_{X_{(1)},X_{(2)},..., ...
0
votes
0answers
7 views

Research on debt recovery

My final year project is on debt recovery data for a debt collection firm. Data such as original/current balances,payments made,DOB, number of contacts made,whether or not a debtor has made insuarance ...
0
votes
1answer
9 views

Differences in SVM performance

Why would a polynomial SVM have better performance than a linear SVM but the same performance as a radial SVM?
0
votes
0answers
4 views
0
votes
0answers
4 views

Transforming data for canonical correlation analysis

Okay, I'm a stats newbie so I'll try to be as specific and clear as possible. I have a set of predictor variables (2 predictor variables) and a set of response variables (7 response variables). I am ...
0
votes
1answer
12 views

Using OLS for Model Selection and Prediction - Heteroscedasticity Issue

I am new to regression and having problem in solving Heteroscedasticity in OLS. Have done lots of homework and test before seeking your advice. Sharing the background and what I have done to solve the ...
0
votes
0answers
10 views

Predictive modeling techniques for in-sample rather than out-of-sample prediction?

Is it appropriate to apply predictive modeling variable selection and shrinkage techniques (for example, ridge regression or lasso) for in-sample prediction rather than out-of-sample prediction? ...
0
votes
2answers
6 views

SVM and kernels

Suppose you are given a binary classification problem. How do you know that you have to map the problem into a higher dimensional space? In other words, how would you know that a linear SVM is not ...
2
votes
2answers
47 views

About cross-validation for machine learning

Assume I have 1000 samples of data. I split the data randomly into training and test sets of size 800 and 200, respectively. Now, I train a classifier using the training set, and then evaluate the ...
2
votes
2answers
36 views

If $X \sim$ unif$(0,1)$, what is the distribution of $U=\max \{X,1-X \}$?

Let $X$ be uniformly distributed in $(0,1)$ and set $U=\max \{X, 1-X\}$. How can I find the distributiopn of $U$? My first thought was to consider this a mixture distribution problem and use the CDF ...
1
vote
1answer
8 views

Find the effect of a attribute value on an outcome by eliminating confounding values

I have a series of lets say five attributes. The first attribute is called diagnosis code 1, the second diagnosis code 2 etc. The values are codes which represent diseases. In other words, each ...
0
votes
1answer
15 views

interpreting my own data (negative confidence interval in epidemiology)

Im trying to measure the absolute change between two means of systolic bloodpressure, and used a simple method for calculating the confidence interval between to means. My goal is to estimate the ...
0
votes
0answers
7 views

One sample Hoteling's T2

I used one sample Hotelling's T2 statistic to check if the nutrient intake of 75 men meet the recommended daily nutrient intake value. I got an F value close to 58000. Is such a large value ...
1
vote
1answer
10 views

Is there a significantly different number of people between groups?

How do I estimate whether a given number of people across groups (say, 72 people in group 1, 95 in group 2 and 70 in group 3) significantly differs from a random distribution of people across groups? ...
2
votes
2answers
27 views

K means cluster analysis

I used two variables height and weight and using K (=2) means cluster analysis 2 clusters were obtained. I used k=2, as the observations either belong to men or women. I then compared the obtained ...
0
votes
0answers
6 views

How to calculate prediction intervals in major axis regression using R

Need help in calculation of prediction intervals in major axis regression (MA). I'm using 'lmodel2' package for calculation of the MA, but I don't understand how to calculate prediction intervals ...
-2
votes
0answers
22 views

the Dempster-shafer theory [on hold]

I want to use dempster-shafer theory to compute certain threshold. I want to ask you if someone have documentation or suggestion about this problem. thank you
0
votes
0answers
22 views

How many samples do I need to prove that a classification algorithm is better than another?

I have two algorithms A and B, used to automatically classify each of N elements into K categories, N and K both being in the millions. Neither A or B is perfect, but it is relatively easy for a human ...
0
votes
1answer
7 views

Interpretation of two indexes Interaction Term

Respected Fellows. I will thankful if someone help me to explain my model results.my model is as follows. Yit=αPFit+βPSit+δ (PF*PS) it+εit Where Y is GDP per capita PF=Political Freedom Index ranges ...
0
votes
0answers
15 views

Which Test to Use?

I was wondering if someone could help me regarding the statistical tests I should use. Basically I have the following: 1) I carried out a survey asking teachers and students to rank components in my ...
0
votes
0answers
7 views

How to use Hartemink's discretization algorithm?

From the help documentation of the discretize function of the R package bnlearn: Hartemink's algorithm has been designed to ...
3
votes
2answers
44 views

Proving some properties of expected first order statistics with respect to sample size

Question: Consider $n$ random variables $x_1, x_2,\cdots x_n\sim \mathcal{N}(0,1)$. The expected value of the $i$th order statistic (the maximum) can be written as $E(\mathcal{O}^n_1)= ...
1
vote
1answer
26 views

Does the vanishing gradient in RNNs present a problem?

One of the often cited issues in RNN training is the vanishing gradient problem [1,2,3,4]. However, I came across several papers by Anton Maximilian Schaefer, Steffen Udluft and Hans-Georg Zimmermann ...
3
votes
1answer
19 views

wilson's adjustment for sample proportion

Could somebody provide a derivation for Wilson's adjustment for the CI of a sample proportion? The formula is: $$\tilde{p} \approx \frac{x+2}{n+4}$$ where $x$ is the number of successes, and $n$ is ...
0
votes
0answers
10 views

How to extract the importance of predictors in Adaptive boosting?

I have trained a boosting classifier using ada package in R. Now I want to see the importance of my predictors in constructing ...
0
votes
1answer
11 views

Covariance estimation

Suppose I want to estimate the covariance of $n$ $p$-dimensional iid random vectors $X_i$, where $n>p$. I've read in several places that if $n-p$ is small then the MLE covariance matrix estimate ...
1
vote
0answers
21 views

Relation between entropy and information

In terms of compression and information theory, the entropy of a source is the average amount of information (in bits) that symbols from the source can convey. Informally speaking, if we are certain ...
0
votes
0answers
10 views

Naive Bayes classifier calculation

I'm trying to use naive Bayes classifier to classify my dataset.My questions are: 1- Usually when we try to calculate the likehood we use the formula: P(c|x)= P(c|x1) * P(c|x2)*...P(c|xn)*P(c) . But ...
0
votes
0answers
13 views

Intervention Analysis - Pulse over several periods

I have a couple weekly time series and an intervention occurred over several weeks and then for some, after a period of no intervention, began again. So, the pattern is off for a period of weeks, then ...
0
votes
1answer
10 views

Is my (SPSS) independent t test correct, and how should I intrepret it?

I have a sample size of 158 students belonging to IT(N=77) and non-IT disciplines(N=81). I have carried out the independent sample t-test but I am not sure whether it's correct or not. Moreover, ...
0
votes
0answers
11 views

Stack of HMMs. Does this have a name?

Consider a sequence of tokens. One could fit a Markov model to this sequence by computing the empirical stochastic transition matrix. A refinement to this model would be to build a HMM on top of it, ...
1
vote
1answer
44 views

Getting Residuals to be White Noise

I'm on a time series project for an undergraduate course. For the project I'm trying to come up with an ARIMA model for the housing starts data set. ...
1
vote
2answers
28 views

Why representation of AR process comes up in estimation

Let ${X_t}$, $t=...-2,-1,0,1,2...$ be a stochastic process that satisfies: $X_t=\rho X_{t-1}+\varepsilon_t$ with $|\rho|<1$ and $\varepsilon_t$ is a white noise. In that case, we also know that ...
0
votes
1answer
21 views

Why does maximum likelihood estimation not work in estimating signal in deterministic chaotic noise

I have few conceptual questions related to application of chaos in communications. In few application such as radar Chaotic signal reconstruction with application to noise radar system, cryptography, ...
0
votes
0answers
13 views

How do I estimate a time series regression using GMM in the way proposed by Acosta-Ormaechea and Morozumi (2013)?

In their paper Acosta-Ormaechea and Morozumi (2013) propose a use of GMM for estimating a regression in which they try to find the impact of reallocating public expenditure from some unproductive to ...
1
vote
0answers
7 views

Estimating workers within Industry Sector using commuter data (combining probabilities?)

I have some detailed data about the commuting patterns of workers. If I know the following 3 things... The total number of workers commuting from one block to another. The total # and % of ...
2
votes
1answer
15 views

C-Test for comparing poisson means in Scipy

I'm relatively new to stats, and I have a large dataset of strings (n=114541) for which I'm interested in a binary event: whether X occurs or not (specifically, whether a specific language construct ...
1
vote
0answers
8 views

Calculating upper and lower confidence limits on a population estimate derived from multiple point estimates

I am generating a river reach population estimate for a freshwater mussel by summing point estimates made across a gridded point network (within the reach) using a generalized linear mixed model ...
1
vote
1answer
19 views

Have conducted a bivariate correlation - want to identify the outlier - is there a 'statistical' way to do this?

I run correlation (on SPSS) between a governance indicator 1996 and the same governance indicator in 2012. As would be expected there is a near perfect correlation. What I am interested in, however, ...
0
votes
0answers
7 views

Neighbours list extracted out of polygon regions [migrated]

I've got a SQL database which contains some coded polygon structures. Those can be extracted as follows ...
4
votes
2answers
142 views

How odd is a cluster of plane accidents?

Does this quotation from the news media make sense, or is there a better statistical way of viewing the spate of recent plane accidents? "However, Barnett also draws attention to the theory of ...
0
votes
0answers
9 views

Propensity in linear models and bilinear regression models

I'm reading this paper about matrix factorization. In the paper they want to combine the features of the nodes in the model (page 6). First they illustrate the simple idea of combining the features of ...
2
votes
1answer
22 views

Choosing variable transformations in non-linear relationships

I am confused about how to apply a transformation to my predictor/response variables to test curvilinear relationships. I read about log transformations, polynomials, quadratic functions. But I am not ...

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