0
votes
0answers
4 views

Performance comparsion study on real data in Matlab (machine learning)

I need to compare performance using 2-classes' classifier – LDA classifier and Exact Bayes in Matlab. I have to use this dataset – http://archive.ics.uci.edu/ml/datasets/Skin+Segmentation. Can anyone ...
0
votes
1answer
11 views

Sum of squared errors

Why do we use SSE (the sum of squared errors) in calculations. Why do not we use the sum of errors? Could you explain please?
0
votes
0answers
5 views

3x2 design - data analysis ANOVA/MANOVA? How to add interaction in the model?

Discription of experiment I am researching "The effect of review valence and brand commitment on consumer's purchase intention" for my university thesis. I conducted a 3x2(no review/positive ...
0
votes
0answers
13 views

Difference in AIC and BIC values between sem and lavaan packages in R

I ran the same SEM model in sem and lavaan. I got the same parameters and - generally - very close test values, with the exception of AIC and BIC which were immensely different between the two ...
0
votes
0answers
3 views

How to extract long run and short run coefficients from ARDL (UECM) estimates?

I have estimated ARDL(UECM) in eviews but I dont know how to specify or extract the long run an short run estimates/coefficienst? what is the standard procedure to do so?
1
vote
1answer
19 views

When to use CDF and PDF for Exponential Distribution

I am doing a self-study on Exponential Distribution and noted an exponential on my text giving that: CDF of Exponential Distribution $$ F(x) = 1 - e^{-λx} , $$ PDF of Exponential Distribution $$ f(x) ...
0
votes
0answers
5 views

Normalizing Data in Multiple Categories

I couldn't decide if this question belonged here or on the Math stack exchange, but I'm posting it here since it seems more directly relevant. Basically, I have a bunch of categories, labeled, say, ...
0
votes
0answers
13 views

Likelihood Ratio Tesr

Let X1;X2; :::;Xn be a random sample from N(0; 2 = ) distribution where 0 < < 1 and 0 is known. Show that the likelihood ratio test of H0 : = 0 versus H1 : 6= 0 can be based upon the ...
0
votes
1answer
7 views

Is it OK to increase validation checks and decrease min gradient while training neural network?

My input vector is a 130*85 matrix and my target vector is 130*26 matrix. I am using the below parameters for training the network with 60 hidden nodes. ...
0
votes
0answers
6 views

Sample size for binary/categorical variables

I have a data set composed by 1000000 projects. Each project is characterized by its size in terms of KBs and a binary variable that is 1 whether the project is active, 0 otherwise. The distribution ...
0
votes
0answers
7 views

Statistics of time dependent variable observable only at end-of-life given survival data

I have a variable whose value I can only measure at the end of life of a product (which is not fixed). The variable's value, continuous and between 0 and 100, may be related to its age at that time. ...
1
vote
2answers
27 views

What problems do non-normality in predictor variables cause for a multiple regression analysis?

I am talking about a situation in which I have several continuous predictor variables predicting a continuous outcome. One of the predictors has a very non-normal distribution and has some wild ...
0
votes
1answer
16 views

Comparing proportions

I have a sample of 65 participants. 20 chose A. 18 chose B. 14 chose C and 13 chose D. What is the suitable test to determine if there is significant difference in the proportions?
0
votes
1answer
15 views

Continuity correction error when using normal distribution to estimate Poisson distribution

Good morning Everyone, I am doing a self-study exercise which attempts to exemplify a case where the Normal Distribution is used to approximate the Poisson Distribution, since the population mean is ...
-4
votes
0answers
25 views

HOW TO DRAW SCATTER GRAPH FOR MY CLUSTERING OUTPUT

num = data(a1(k1):b1(k1),3); CE=0;SX=0;DM=[]; m=mean(num); %mean value calculation S=nanstd(num); DI=pdist2(num,m,'seuclidean',S); sn=size(DI); nmin=2*100/2; dmax=max(DI); ...
1
vote
0answers
9 views

How can I interpret the results of LSA?

I implemented LSA on MATLAB. I have a $D\times N$ term-document matrix, where $D$: # of words, $N$: # of docs. I did low-rank approximation using SVD, and got $$X_k = U_k \cdot S_k \cdot V_k' ...
0
votes
0answers
8 views

Interpreting Multivariate probit

How do you interpret the results of a multivariate probit regression? Is it interpreted the same way as OLS?
0
votes
0answers
14 views

Movie recommendation problem

I have a set of data with features of movies and features of users and a third matrix with ratings of user for each movie. I have to build a recommendation system for new users. Can you help me with ...
0
votes
0answers
19 views

Finding Percentage Point of a Normal Distribution

Good evening all, I am doing a self-study exercise, but have been quizzed by a part of the question on finding percentage points of a normal distribution. I fully understand the first part of the ...
0
votes
0answers
9 views

Where is my mistake in the following example about Viterbi algorithm?

I am trying to learn Hidden Markov Model, Viterbi algorithm. Therefore I was looking for an example to study. I came across a simple example from the website below; ...
2
votes
0answers
24 views

A case of understanding customer behavior

Suppose I have a big online company, and many of my customers churned (i.e. they were paying, and then stopped). My goal is to understand why each of them churned. First I identify the complete set ...
-2
votes
0answers
16 views

how to code a random intercept and slope in a mixed linear model and apply LAM in SAS

I m a PhD student in New Zealand. I need to determine the impact of lameness in milk yield of cows. I measured milk yield daily as well as I recorded the cows that were observed lame in any one day . ...
0
votes
0answers
20 views

What is the code for cubic spline regression model in SAS

I ran an experiment that identified lame and non-lame cows every day for 325 days from a pool of 936 cows in one herd. At the same time, I collected data on various variables like milk volume, fat and ...
0
votes
1answer
14 views

What kind of distribution is this via t-distribution

Suppose we repeat an experiment identically and independently 100 times. Each time we construct a 99% confidence interval for $\mu$ via the t-distribution. Let X = the number of times the confidence ...
0
votes
0answers
9 views

Inference with only left-censored data

Suppose I have a data set that is only left-censored data, ex: <5, <5, <5, <10, <10, <10 A technique to handle left-censored data is the Kaplan Meier estimate, see page 5 of ...
3
votes
1answer
41 views

Not sure I understand how R calculates the covariance

Please forgive this silly question, I'm fairly new to statistics. Consider this R code: ...
1
vote
1answer
12 views

Does the estimated overdispersion parameter of Negative Binomial depend on mean

Negative Binomial distribution can be parameterized using mean, $\mu$, and overdispersion $\psi$, so that the variance of NB is $\mu + \frac{\mu^2}{\psi}$. We know there is no analytical solution for ...
1
vote
1answer
16 views

JAGS meta-analysis

I'm using JAGS to run a meta-analysis and I've run into an issue. I have calculated log-response ratios and errors for about 177 studies, where studies fall into one of 8 groups. I'm interested in ...
2
votes
1answer
29 views

Hierarchical Bayesian modeling of incidence rates

Kevin Murphy's book discusses a classical Hierarchical Bayesian problem (originally discussed in Johnson and Albert, 1999, p24): Suppose that we are trying to ...
2
votes
1answer
34 views

Finding an equation with many variables to fit a set of data

I am writing a program which takes notes from a keyboard as the input, (just numbers, 1 to 88) and decides which notes are played by which hand. There are a lot of variables, for example, the position ...
2
votes
0answers
16 views

How to subset alternatives in nested multinomial logistic regression?

I am trying to predict whether or not captains in a particular groundfish fishery choose to fish on any given day and what variables may influence that decision. Originally I had planned on using ...
1
vote
2answers
26 views

SVM for unbalanced data

I want to attempt to use Support Vector Machines (SVMs) on my dataset. Before I attempt the problem though, I was warned that SVMs dont perform well on extremely unbalanced data. In my case, I can ...
2
votes
2answers
56 views

Why we shouldn't be obsessed with unbiasedness

In my Bayesian statistics class, my professor makes the remark that we should not be obsessed with unbiased estimator. First: I understand this statement in the sense of trading biasedness for ...
1
vote
0answers
16 views

Comparing nested, non-linear models

I would like to compare the fit of two non-linear regression models: 1) $$ Y = (\Pi^{10}_{i=1}\beta_i^{x_i})^{1/\Sigma \beta} $$ 2) $$ Y = \begin{cases} (\Pi^{10}_{i=1}\alpha_i ...
1
vote
0answers
19 views

Should I be using a Welch or standard T-test?

I'm really confused here. I am trying to compare two sets of data which differ in sample size. One has 257 entries and the other has 598. They are measures of scores on two different assessment types ...
1
vote
1answer
42 views

Regresssion of Accurate Data

I'm collecting calibration data for a device which involves three variables $S$, $L$, and $x$. For a given coordinate $(S, L)$, the device will provide me with the corresponding value of $x$ to a high ...
1
vote
1answer
45 views

When to use Bayes' theorem to calculate conditional probability?

Given 2 events $E, F$, I know that $P(E | F) = \frac{P(E \cap F)}{P(F)}$. However sometimes the Bayes' theorem is used instead: $P(E | F) = \frac{P(F | E) P(E)}{P(F|E)P(E)+P(F|E^{c})P(E^{c})}$. ...
0
votes
0answers
9 views

ARMA Model Output & Excel

I am using my Eviews Output of an ARMA Model, taking the coefficients in other to perform my Forecasts in Excel. However, I am not being able to match the residuals of the in-sample estimations ...
0
votes
0answers
15 views

Cummulative Mixed Model in R variable names

I'm trying to fit a cumulative link mixed model clmm() in Rstudio. I'm currently having issues with the diagnosing what is wrong with my model from the output I am getting. The output I got from my ...
0
votes
0answers
8 views

Comparing Overlapping Percentages

I observed how frequently participants exhibited five specific behaviors during testing. The total of the below percentages exceeds 100%, because some participants (30.43% of the sample) exhibited ...
0
votes
0answers
9 views

MC Integration Interval Probability [duplicate]

We were asked this question for homework: B. Use MC integration to estimate the probability that X · exp(X ) < 2.5, assuming that X ∼ Gamma(1.2, 3.7). Details. The PDF, CDF, and QUANTILE ...
6
votes
2answers
94 views

How to properly handle Infs in a statistical function?

Suppose I have a function such like: f <- function(x){ exp(x) / (1 + exp(x)) } it's supposed to work for any real value of x, but actually it returns NaN ...
1
vote
1answer
35 views

Can a machine learning algorithm be evaluated based on a random sample?

I am trying to evaluate how well (or bad) a semi-supervised algorithm is performing on a given dataset. The algorithms assigns one of 10 labels to each data point. The dataset is huge, and it's not ...
1
vote
0answers
5 views

Correlated Random Effects Probit vs. GEE Population-Averaged Probit

My question relates to recent work on correlated random effects probit models (see these slides from Wooldridge) and comparing them to GEE population averaged probit models: Is one approach better as ...
0
votes
0answers
20 views

MAP Estimator with Laplacian Noise

I need to calculate the MAP estimator of $ x $ in the following case: $$ \left [ \begin{matrix} {y}_{1}\\ {y}_{2} \end{matrix} \right ] = \left [ \begin{matrix} x\\ x \end{matrix} \right ] + ...
0
votes
0answers
32 views

Identifiability in linear regression

If we have a generative model: $X_2=X_1a_1+\varepsilon$, where $\varepsilon \sim \mathcal{N}(0,\sigma_2^2)$, do we have $X_1=X_2a_2+\varepsilon '$, where $\varepsilon \sim \mathcal{N}(0,\sigma_1^2)$ ...
0
votes
1answer
92 views

What does the | in |Z| mean in mathematical expressions for distribution statistics

I am doing some self study on statistics and noticed that in the notes that I was using the $|Z|$ expression as attached in the photos below. I am confused with the "$|$" that is being used. The only ...
0
votes
0answers
8 views

which test to use here to test the significance of overlap with respect to a control?

i'm not sure what statistical test to use to compare a scenario like this: I have a list of candidate regions A (560k regions) and I want to know if my candidate regions enrich for a particular set ...
1
vote
0answers
35 views

What to do with missing values?

I have missing values for some of the variables in my data. I am using pooled OLS and have 144 observations. I have missing values for three of the variables. Less than 10% of the data for each ...
4
votes
0answers
21 views

R packages that work with biased samples

I'm working with a biased sample of web users. I'm only able to track responses of users who have navigated my site in a certain way, and I'd like to run an analysis to determine how certain factors ...

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