question stringlengths 37 38.8k | group_id int64 0 74.5k |
|---|---|
<p>I want to use a global optimization algorithm to find the optimum set of values for n variables (n>100) and all variables take binary values (0 or 1).
I am thinking in Genetic Algorithm, Particle Swarm Optimization, Differential Evolution (others?). But, which of them is suitable for integer (binary) variables?</p>... | 30,716 |
<p>I have a data asset where one "unique"ID corresponds to multiple cases, shown below. I am looking for a way to create a column ranking each ID by another column but keeping the rank unique for each ID. </p>
<pre><code>ID number Rank(column I'm trying to add)
1 55 3
1 40 2
1 ... | 70,012 |
<p>Given that statistics can often be abused to deliberately present 'facts' to support a pre-existing viewpoint. (Lies, damned lies and statistics).</p>
<p>And given confirmation bias.</p>
<p>Is there an established method of choosing <em>which</em> statistics to use, which ensures (or at least endeavours) to be as ... | 70,013 |
<p>I am trying to get an intuition to the concept of uniform integrability:
$$
\lim_m \sup\lim_n \mathbb{E}[|X_n| I_{\{X_n \geq m \}}] \to 0
$$</p>
<p>Can this be seen as a form of "asymptotic light tails"? Can this intuition be formalized? </p>
<p>And also- is this the same as the Lindeberg condition for the CLT?</p... | 70,014 |
<p>When trying to perform a univariate <em>mixture model</em> estimation, <code>R</code> package <code>mclust</code> produces the following <em>output</em> with an <strong>error</strong>:</p>
<pre><code>----------------------------------------------------
Gaussian finite mixture model fitted by EM algorithm
---------... | 70,015 |
<p>I have written a dozen scientific papers and posters about medical trials and psychological trials with a lot of statistical analysis, and a common question "perturbed my certainties":</p>
<blockquote>
<p>How do I write statistical significance so that it is easy to read, and avoids repetition and panegyric?</p>
... | 2,007 |
<p>My questions are: </p>
<ol>
<li>Are generalized linear models (GLMs) guaranteed to converge to a global maximum? If so, why? </li>
<li>Furthermore, what constraints are there on the link function to insure convexity?</li>
</ol>
<p>My understanding of GLMs is that they maximize a highly nonlinear likelihood functi... | 70,016 |
<p>I collected data of 60 countries to identify whether there is a relationship between average income per person and average life expectancy. However, I am having some trouble interpreting my lin-reg and r value. </p>
<pre><code>y = 0.000437x + 67.68
r = 0.814
</code></pre>
<p>Does this inconsistency have to do with... | 70,017 |
<p>I just have a quick question about MLE.</p>
<p>Sometimes, when doing MLE problems, I see that the variance expression gotten from the inverse of the Fisher Information is exactly like what it should be and sometimes it isn't. Is there a reason that for some distributions this method is exact? Also, why is it that f... | 70,018 |
<p>This is an end-of-chapter question from a Korean textbook, and unfortunately it only has solutions to the even-numbered q's, so I'm seeking for some hints or tips to work out this particular joint moment generating function question. or I better state that I cannot find a way to solve this particular double integral... | 30,720 |
<p>When we conduct an ANOVA, we get F-Value and P-Value. If P-value if smaller than our alpha level of .05 for example, we reject our null hypothesis. What is the importance of F-Value that is obtained in the table as output? How it should be interpreted especially when conducting a within-subject ANOVA test?
Thanks</p... | 49,384 |
<p>I'm measuring running times of two programs on $n$ inputs and I want to know whether one of the programs is faster. Each program has 30 seconds and 8 GB of memory for processing one input. If the program successfully solves the problem within the limits I record its running time, otherwise I record <code>t</code> wh... | 30,723 |
<p>I have a dataset with a small number of input points (e.g. +- 300), but millions of boolean outcomes. </p>
<pre><code>Input: Observations: #True: #False
10 100 51 49
12 120 55 65
...
300 1000 430 570
</code></pre>
<p>I would like to use a Gaussian... | 30,724 |
<p>I am newbie in the field of object detection and object description algorithms. I need tutorials for Brisk Algorithm or can someone please explain in simple terms how the algorithm works?
Thank you</p> | 70,019 |
<p>I read very carefully the answer to the question "what is deviance?" already asked <a href="http://stats.stackexchange.com/questions/6581/what-is-deviance-specifically-in-cart-rpart">here</a>, and I understand how to calculate and use deviance for model comparison, for example.</p>
<p>However, a question remains as... | 381 |
<p>My apologies for another stats beginner question. This feels like reinventing the wheel, unfortunately I just can't find the answer myself. Googling "average densities classification" does not help me. </p>
<p>"classifying using histogram" brings up interesting pages, but <a href="http://cs.ecs.baylor.edu/~hamerly/... | 70,020 |
<p>Why do we need to include precision variables in a regression model (i.e., a variable that is associated with the outcome but not the predictor of interest)?</p> | 70,021 |
<p>It is fairly straightforward to compute the inverse cdf a gaussian mixture model by doing sampling (first selecting a component of the mixture according to the coefficient of the component, then sampling q ~ U(0,1) and then returning the inverse cdf of that gaussian at q). Of course, this seems pretty computational... | 30,726 |
<p>i'm new in statistics. hope you can help me on the following:</p>
<p>i want to use least trimmed squared (LTS) for regression. below is the <strong>coding in R</strong>:</p>
<pre><code>lts2_M1<-function(failure)
{
library(MASS)
y_log<-failure[,1]
x11<-failure[,4]
x2<-failure[,3]
fit0<-lqs(y_log ~ x1... | 30,727 |
<p>Phase space learning <a href="http://cseweb.ucsd.edu/users/gary/pubs/nips94.pdf" rel="nofollow">Paper1</a> and <a href="http://gliamac.mit.edu/people/seung/papers/continuous.pdf" rel="nofollow">Paper2</a> in neural network represents the input in higher dimension in auto associative learning. So, the network functi... | 70,022 |
<p>There are several concepts for classification performance : precision, negative predictive value, recall, and specificity. </p>
<p>Why do people often choose only precision and recall together ?</p>
<p>Why not negative predictive value or specificity?</p>
<p>Why do they choose F score in addition to precision and... | 70,023 |
<p>I built a learning model (for classification) based on a Random Forest classifier and i am asked to assess the statistical significance of its performances. </p>
<p>Up to now, i trained and tested it on two different datasets A and B, respectively.</p>
<p>What kind of test can i use?</p> | 70,024 |
<p>I need to compute the sample-adjusted meta-analytic deviancy (SAMD) as part of an outlier search with meta-analytic data. Because we have a very large amount of meta-analytic data, computing this statistic by hand would take a little longer than forever. Does anyone know of an SPSS, Excel, or MPLUS syntax/macro avai... | 30,730 |
<p>I am doing a statistical analysis of variations in anatomical features, for example the shape of a pelvis bone. I found out that morphometric method can be used to quantify differences in geometry (e.g. shape and texture). My question is, what kind of method can I use to predict the shape variation of an anatomical ... | 70,025 |
<p>What do you recommend?</p>
<p>I planned to do repeated-measures ANOVAs on 3 sets of data collected at 3 different points in time (initial n=1,500). The first data set appears to be non-normally distributed, and so I`ve gone on to do a series of Kruskal-Wallis H tests in SPSS (the independent variable has 4 groups, ... | 70,026 |
<p>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 <a href="http://www2.imperial.ac.uk/~das01/Papers/poprev.pdf" rel="nofollow">here</a> gives a good summary of population MCMC. In most papers I have r... | 70,027 |
<p>I'm doing an experiment where peaks in amplitude $A$ (the dependent variable) are expected as one varies the frequency $f$ (the independent variable). </p>
<p>Based on our theoretical model,</p>
<ul>
<li>Away from the peaks, the value for the amplitude is approximately zero.</li>
<li>Close to the peaks, the amplit... | 70,028 |
<p>We conducted a parallel experiment with the conventional wet chemistry analysis for Sugar Cane sample for parameters POL, BRIX and Fibre content for payment purposes with Near Infrared Spectroscopy.</p>
<p>We have developed a calibration equation for three parameters and the result for $R^2$ are as follows: 0.9 POL... | 70,029 |
<p>Tennis has a peculiar three tier scoring system, and I wonder if this has any statistical benefit, from the point of view of a match as an experiment to determine the better player.</p>
<p>For those unfamiliar, in normal rules a game is won by the first to 4 points, so long as you have a 2 point lead (i.e. if it is... | 43,577 |
<p>I have a data set containing the number of actions performed by individuals over the course of 7 days. The specific action shouldn't be relevant for this question. Here are some descriptive statistics for the data set:
$$ \begin{array}{|c|c|} \hline \text{Range} & 0 - 772 \\ \hline
\text{Mean} & 18.2 \\ \hl... | 70,030 |
<p>I am currently working on a model for exchange rates, and I want to use an ARIMA-GARCH specification. More precisely, I work on the log-returns series. </p>
<p>First of all, I perform multiple KPSS and ADF tests to get the conclusion that the series is stationnary up to a trend. I then use the auto.arima function t... | 70,031 |
<p>I am doing time series data analysis by state space methods. With my data the stochastic local level model totally outperformed the deterministic one. But the deterministic level and slope model gives better results than with stochastic level and stochastic/deterministic slope. Is this something usual?
All methods ... | 41,181 |
<p>The Pareto distribution can be used to give a pdf for the wealth of a person chosen randomly from a population. (In fact, this was its origin. See, for instance, <a href="http://en.wikipedia.org/wiki/Pareto_principle" rel="nofollow">http://en.wikipedia.org/wiki/Pareto_principle</a> ).</p>
<p>I would like to explo... | 70,032 |
<p>I want to approximate a non-linear function with a limited value range by an artificial neural network (feed forward, back propagation).
Most tools and literature availabe suggest linear functions for the output neurons when doing regressions. However, I know a priori that my goal function is of limited range, there... | 30,738 |
<p>I have just done a Chow test on a regression in order to see whether there is a structural break. I am a bit stumped however as my Chow test returns a negative number. Now what do I do?</p>
<p>More specifically, this expression (from the Wikipedia <a href="http://en.wikipedia.org/wiki/Chow_test" rel="nofollow">entr... | 70,033 |
<p>We are using <code>lavaan</code> in <code>R</code> to calculate CFAs (confirmatory factor analyses) and SEMs (structural equation models). We now want to test whether two latent constructs can be assumed to be unrelated (discriminant validity).</p>
<p>Refering to </p>
<blockquote>
<p>Fornell, C. & Larcker, D... | 70,034 |
<p>I use four feature descriptors for five independent runs with each run randomly selecting the training set and testing set from the total labeled samples. SVM is the classifier. After acquiring the classification accuracy of each run for each descriptor, I get a accuracy matrix whose size is $5 \times 4$. Then I use... | 70,035 |
<p>I am currently working on a programme to compute the mutual information between a variable and a set of variables. Since I am working with discrete data, I am computing $\sum_{a\in A,b\in B,c\in C}P(A=a,B=b,C=c)*\log_{2}({P(C=c)P(A=a,B=b,C=c)\over P(A=a,C=c)*P(B=b,C=c)})$ where I look up in my DataBase, how often th... | 70,036 |
<p>I would appreciate some advice on how best to weight or give more importance to a percentage with a larger denominator.
Eg</p>
<ul>
<li>A. 1 out of 2 = 50%</li>
<li>B. 5 out of 10 = 50%</li>
<li>C. 500 out of 1000 = 50%</li>
</ul>
<p>Some of the data is sparse and continually emerging so </p>
<ul>
<li>A) could ju... | 41,194 |
<p>I am trying to simulate a selection model for a variable $Y$ dependent on covariate vector $X$, so that two groups/sub-sets $S=(0,1)$ of observations on $Y$ are created, which have a fixed difference in expectations (means) $\theta$ (i.e., selection bias) $$E(Y|S=1)-E(Y|S=0)= \theta$$ </p>
<p>I am looking for solut... | 70,037 |
<p>I have quarterly sales data for a variety of stores and would like to estimate the effect of a regulation on sales. A panel type model would appear to be appropriate in this case, with the regulation as a dummy variable.</p>
<p>However, the quantity of sales varies by two-orders of magnitude between stores. How s... | 70,038 |
<p>I'm trying to implement a "change point" analysis, or a multiphase regression using <code>nls()</code> in R. </p>
<p><a href="http://i.stack.imgur.com/27f1S.png">Here's some fake data I've made</a>. The formula I want to use to fit the data is:</p>
<p>$y = \beta_0 + \beta_1x + \beta_2\max(0,x-\delta)$</p>
<p>What... | 49,308 |
<p>Is there a k-way MinMax Cut Spectral Clustering which can be easily implemented? In the spectral clustering tutorial I found only 2-way MinMax cut.</p> | 33,955 |
<p>From Wikipedia :</p>
<blockquote>
<p>Suppose you're on a game show, and
you're given the choice of three
doors: Behind one door is a car;
behind the others, goats. You pick a
door, say No. 1, and the host, who
knows what's behind the doors, opens
another door, say No. 3, which has a
goat. He then sa... | 49,611 |
<p>What topics in statistics are most useful/relevant to data mining?</p> | 70,039 |
<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://stats.stackexchange.com/questions/30/testing-random-variate-generation-algorithms">Testing random variate generation algorithms</a> </p>
</blockquote>
<p>What's a good way to test a series of numbers to see if they're random (or at least p... | 49,380 |
<p>What are pivot tables, and how can they be helpful in analyzing data?</p> | 70,040 |
<p>I'm testing different ways to fit a simple power model to a dataset of 5 points. </p>
<p>I don't get same results if I use nls on non-transformed data or lm on log10 transformed data in R whereas Excel gives exactly the same results (it's power fitting might be a hidden linear fitting on log transformed data).</p>
... | 70,041 |
<p>There has been a lot of attention on Big Data recently, where the problems are often more logistical (how to deal with large volumes of data) rather than statistical. At the other end of the spectrum we have "small data", where there is no logistical problem, but instead we have the problem of how to estimate the p... | 30,748 |
<p>How can I create two random sequences of numbers that are $50\%$ correlated to each other? Each sequence has a different variance.</p> | 49,333 |
<p>I'm looking for some ideas on how I can estimate the results of a particular calculation on a data set. The data is a very simple mapping of X=>Y where X is a real value and Y is a positive integer. The calculation that needs to be performed is given value Q what is the sum of all Y having X < Q.</p>
<p>What I w... | 30,751 |
<p>I have 50 data sets. Each set has three related time series: fast, medium, slow. My end purpose is simple, I want to generate a number that indicates a relative degree of change of the time series at each point. That relative degree of change should range between 0-1 for all the time series and all the data sets. Th... | 70,042 |
<p>The von Mises distribution is entirely defined on the circle with a density given by
$$f(x) = (2\,\pi\, I_0(\kappa))^{-1} \exp(\kappa \cos(x-\mu))\ ,$$
where $x$ is in an arbitrary real interval of length $2\pi$, $I_0$ is the Bessel-I function of order 0, $\mu$ is a location parameter, and $\kappa>0$ is a concen... | 70,043 |
<p>Here is a sample output:</p>
<pre><code>anova(fit1,fit2);
Quantile Regression Analysis of Deviance Table
Model: op ~ inp1 + inp2 + inp3 + inp4 + inp5 + inp6 + inp7 + inp8 + inp9
Joint Test of Equality of Slopes: tau in { 0.15 0.3 }
Df Resid Df F value Pr(>F)
1 9 1337 0.5256 0.8568
Warning messages:
... | 30,752 |
<p>I have <a href="http://stats.stackexchange.com/questions/8407/import-stock-price-from-yahoo-finance-into-r">stock price data from Yahoo</a> and I have corporate announcements from various RSS feeds that give me the date of the announcement, the date of the quarterly statement, etc. What is the best approach I should... | 70,044 |
<p>I do a multiple regression in which spacing between lines is one of four variables. However, this spacing between lines varies so I have grouped them into five classes designated with numbers 1 through 5. The number 1 represents the case of no lines present; the number 2 represents that the spacing between lines e... | 70,045 |
<p>I am getting the following result for one of my variables after running a logistic regression.</p>
<p><img src="http://i.stack.imgur.com/ofxSF.png" alt="enter image description here"></p>
<p>Basically I have a set of binary dependent and one independent variable. One of the dependent variables is never 0 when the ... | 70,046 |
<p>Suppose you have a six-sided die that you suspect is not fair and toss it N times. What would be a Bayesian approach to estimating the probability of the six outcomes given that you suspect the die may be unfair?</p>
<p>I know that I have to come up with a prior density and a likelihood in order to define what the ... | 70,047 |
<p>I have a linear regression model with 3 independent variables (let's say <code>A1</code>, <code>A2</code>, <code>A3</code>) and 2 different dummy variables, one for the gender (<code>d1</code>) and the other one for the location (<code>d2</code>).</p>
<p>When I estimate the model with all the variables included, so... | 30,756 |
<p>Can I use a point-biserial correlation if my data is not normally distributed and my sample size $N = 120$?</p> | 30,757 |
<p>This is a histogram showing my response variable. </p>
<p><img src="http://i.stack.imgur.com/yJZaQ.png" alt="histogram of response variable"></p>
<p>The response is # (or proportion? or percent?) of aphids eaten off of cards in fields, to model predation by natural enemies. </p>
<p>Predictors: fixed effects are b... | 70,048 |
<p>I have 644 companies out of which 154 went bankrupt. I investigate below if the bankruptcy is related to the sector type:</p>
<pre><code> Bankrupt Nothing total
-----------------------------------
BioTech | 15 110 | 125
Airline | 20 120 | 140
AutoC... | 70,049 |
<p>I have a hypothetical population that contains the values $2,3,4,5,6,7,8,9$. I have to draw a sample of size $4$ from that given population. So I have $\binom{8}{4}=70$ ways to draw the sample. I wrote down all possible samples and computed their sample mean. I got $70$ as the sample mean ($\bar y$). Then I made a f... | 18,066 |
<p>In my research I have 3 domains of IV, 4 of MV and 8 of DV. To run mediation analysis I made possible chains from the results of stepwise regression and only one chain fulfilled the assumptions of mediation. Then I made the possible chains from the results of correlation and 12 possible chains fulfilled the mediatio... | 5,943 |
<p>For an upcoming study of about 200 (rare) cancer cases, we would like to determine the power of detection for a hypothetical marker, present in 10% of cases, i.e. 20 cases with a hazard ratio of 3.0. Cases will be followed up for at least 5 years. We will have the option to validate any identified markers in an inde... | 70,050 |
<p>Is there a (stronger?) alternative to the arcsin square root transformation for percentage/proportion data? In the data set I'm working on at the moment, marked
heteroscedasticity remains after I apply this transformation, i.e. the plot of residuals vs. fitted values is still very much rhomboid. Thanks in advance f... | 70,051 |
<p>I am looking for an easy to use stand alone software that is able to construct <a href="http://en.wikipedia.org/wiki/Bayesian_network" rel="nofollow">Bayesian belief networks</a> out of data. The software should (of course ;-) be free.</p>
<p>Can anybody recommend something? Thank you!</p> | 30,760 |
<p>I'm analysing some data where I would like to perform ordinary linear regression, however this is not possible as I am dealing with an on-line setting with a continuous stream of input data (which will quickly get too large for memory) and need to update parameter estimates while this is being consumed. i.e. I canno... | 49,555 |
<p>I wonder if there is any good and easy to understand book on reviewing on when should a particular statistical model (binomial, logistic regression, etc) be used?</p>
<p>My background is in statistics, but most of my work is developing MLE estimation algorithm using matrix calculus. I am now starting to focus more... | 70,052 |
<p>I have a sample of 100 groups, each with 50 elements. All elements in each group are characterized with a single "size" value.</p>
<p>The sizes of all the elements in a group (with 50 elements) are normalized by dividing them with the size of the maximal element (in their group, regardless of the other 49). Hence I... | 70,053 |
<p>I am dealing with logistic regression, trying to identify variables which have a causal relationship with a binary response. The way I usually do it is to try variables one by one and visualize the probability of positive outcome curve, and check if it is flat or has a good curve. If it is the latter, then it means... | 30,766 |
<p>This is a follow-up but also a different question of <a href="http://stats.stackexchange.com/questions/64587/when-to-use-sample-median-as-an-estimator-for-the-median-of-a-lognormal-distribu">my previous one</a>.</p>
<p>I read on Wikipedia that "<a href="https://en.wikipedia.org/w/index.php?title=Median&oldid=61... | 30,767 |
<p>I want to use supervised machine learning method to do binary classfication, so a training set is needed. I already have the positive examples.</p>
<p>My question is that all my negative examples are randomly selected from a very large dataset which may contain only a few positive examples.</p>
<p>Is this approach... | 70,054 |
<p>I performed multiple pooled cross-sectional regressions with the same time-intervals (5years) in different years. I'm wondering
now on how to aggregate the different regression outputs. Does it make sense to average the estimated coefficients or do you rather use one simple pooled regression over all $t$s? And assum... | 70,055 |
<p>I am involved in the analysis of the effect of an intervention at five different hospitals. The intervention aimed to increase the use of a particular equipement when treeating a patient, so the outcome variable is binary (used the equipement/did not use the equipement). The study is not controlled, just pre- and po... | 70,056 |
<p>I have a sample with little over 100 observations and 50 clusters, one quarter of which have only one observation. Is it correct to calculate clustered standard errors in a linear regression that uses this data or are there some requirements for minimum cluster size and sample size that I am violating? Any reference... | 70,057 |
<p>Suppose that we have two points (the following figure: black circles) and we want to find a value for a third point between them (cross). Indeed we are going to estimate it based on our experimental results, the black points. The simplest case is to draw a line and then find the value (i.e., linear interpolation). I... | 41,227 |
<p>So I have a formula to calculate sample size for a Bernoulli trial, given the inputs of the Delta I wish to detect, and the current probability of a success (click-through rate or CTR).</p>
<p>$N=21*\theta^2/\delta^2$<br>
95% confidence level and 90% power </p>
<p>There are various other formulas one can find... | 41,229 |
<p>I'm building a model in which several of my covariates live on a "circle", in the sense that they take values in the interval [0,1), and 0=1. I'm wondering about techniques for dealing with this situation. One idea is to represent a circular variable theta as a pair of variables ( sin(theta), cos(theta) ). Any th... | 41,230 |
<p>I have a dataset with about 2,000 binary variables/200,000 rows and I'm trying to predict a single binary dependent variable. My chief goal at this stage isn't getting accuracy of prediction, but rather to identify which of these variables are important predictors. I'd like to drop the number of variables in my fi... | 70,058 |
<p>This is a question regarding using logistic regression, and relating it to gaussian distribution or a binomial distribution. </p>
<pre><code>model<-glm(target~ x1, data=data, type='response', family='binomial')
model<-glm(target~ x1, data=data, type='response') #defaults to gaussian
</code></pre>
<p>My und... | 30,773 |
<p>I have a list of websites and Facebook likes count for each of them.
Count varies from 0 to millions.</p>
<p>For each website I want to make up some Score Value from 0 to 10, which would represent sites' social popularity.</p>
<p>Any thoughts how to deal with such a problem would be much appreciated.</p>
<p><stro... | 30,774 |
<p>In my understanding, a time series model is a way to predict the observation. For example, having a time series data points, one possible way to model is using AR model which is $y_{t}$ by $y_{t}= a_{1}x_{t}+a_{2}x_{t-2}+a_{3}x_{t-3}+...+\epsilon_{t} $. </p>
<p>There are many applications in real life using time s... | 70,059 |
<p>I've read a few papers that have used the information theoretic to model selection. One of these papers made 36 candidate models. In the methods section of that paper, the authors mentioned nothing about checking the diagnostics (normality, distribution of residuals, outliers etc) of these models. I'm wondering if t... | 70,060 |
<p>I do not study statistics but engineering, but this is a statistics question, and I hope you can lead me to what I need to learn to solve this problem. </p>
<p>I have this situation where I calculate probabilities of 1000's of things happening in like 30 days. If in 30 days I see what actually happened, how can I... | 49,421 |
<p>Which econometrics book, or any other reference, do you believe provides the most rigorous view of the subject, preferably with proofs and full-blown discussion of mathematical topics?
I mean a book that, for example, has the proofs of the Frisch Waugh, Gaus Markow, Cramer lower bound and the like. The thing is that... | 49,840 |
<p>A well established questionnaire measuring <em>interpersonal</em> relations is modified to measure <em>interorganizational</em> relations. 11 parameters of the relation are determined by 4 items each. Items are removed until the best possible $\alpha$ per scale is achieved (.58 - .81). This results in some scales wi... | 34,138 |
<p>Sampling with replacement has two advantages over sampling without replacement as I see it:</p>
<p>1) You don't need to worry about the finite population correction.</p>
<p>2) There is a chance that elements from the population are drawn multiple times - then you can recycle the measurements and save time.</p>
<p... | 70,061 |
<p>I was reading <a href="http://www.icaew.com/~/media/Files/Events/2012/Regions/london/objectives-of-financial-reporting/financial-reporting-and-firm-valuation.pdf" rel="nofollow">this journal article</a> about the decrease in the relevance of the income statement:</p>
<p>Basically what the author does is this: </p>
... | 70,062 |
<p>Recently I was trying to do logistic regression using the <code>rms::lrm()</code> function. But I had some trouble understanding the model objects from the function. Here is the example from the package:</p>
<pre><code>#dataset
n <- 1000 # define sample size
set.seed(17) # so can reprodu... | 30,781 |
<p>Say that I have two learning methods for a <strong>classification</strong> problem, $A$ and $B$, and that I estimate their generalization performance with something like repeated cross validation or bootstrapping. From this process I get a <strong>distribution of scores</strong> $P_A$ and $P_B$ for each method acros... | 70,063 |
<p>Joris and Srikant's exchange <a href="http://stats.stackexchange.com/questions/2182/can-you-explaining-why-statistical-tie-is-not-naively-when-p-1-p-2-2-moe/2242#2242">here</a> got me wondering (again) if my internal explanations for the the difference between confidence intervals and credible intervals were the cor... | 4 |
<p>here is my scenario:</p>
<p>People record data using sensors, the data is uploaded to a server. Then the users can view their data on a web page. Here is what is in my dataset:
- I know how often each user uploaded a record to the server
- I know if and how often that user viewed his records on the website</p>
<p>... | 70,064 |
<p>I've got a question concerning wheter or not to use an offset. Assume a very easy model, where you want to describe the (overall)number of goals in hockey. So you have goals, number of games played and a dummy variable "striker" which is equal to 1 if the player is a striker and 0 otherwise. So which of the followin... | 41,238 |
<p>Lets say i want to calculate the information content of a particular message.What apart from the message itself has to be taken into account in doing so, and what data would i need to collect to perform my action?</p> | 30,788 |
<p>Especially in the computer-science oriented side of the machine learning literature, AUC (area under the receiver operator characteristic curve) is a popular criterion for evaluating classifiers. What are the justifications for using the AUC? E.g. is there a particular loss function for which the optimal decision ... | 70,065 |
<p>I am searching for a good criterion to measure the "goodness of fit" in generalized linear models. To make clear: I am not searching for a criterion which gives me an answer to the question "does overdispersion occur?". What do you think about Nagelkerke's pseudo R-squared? Any thought would be appreciated!</p> | 30,789 |
<p>Can anyone tell me the factors that affect the memory requirements of $k$-means clustering with a bit of explanation? </p> | 70,066 |
<p>Consider two Wiener processes:
$$
\begin{aligned}
X_a &\sim\mathcal N(0,a) \\
X_{a-b} &\sim\mathcal N(0,a-b)
\end{aligned}
$$
How do I show that:
$$
X_a - X_{a-b} \sim\mathcal N(.,.)
$$
That is, how do I show that $X_a - X_{a-b}$ is Gaussian?</p>
<hr>
<p>I know that $E(X_a - X_{a-b}) = 0$ </p>
<p>and
$$
... | 70,067 |
<p>I need some guidance related to regression model verification using validation data.
I am new to R-tool & statistics and trying my best to learn. I did search on internet too but I couldn't get a final answer to my questions.
Actually I have a lot of questions, I may try my best to explain the problems:
I am e... | 41,243 |
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