question stringlengths 37 38.8k | group_id int64 0 74.5k |
|---|---|
<p>I have an $(x,y)$ dataset consisting of points on an unknown curve and I've been using spline fits to generate a curve joining these points as a guide-to-the-eye (and nothing more). However, I also know $dy/dx$ at each of my points, and so I know that the spline fit is not ideal: e.g. I know that there's a maxima at... | 31,835 |
<p>I'm studying traffic flows, and I'd like to know what are the busiest/most congested roads. From this website <a href="http://www.dft.gov.uk/traffic-counts/about.php" rel="nofollow">http://www.dft.gov.uk/traffic-counts/about.php</a>, it looks like vehicle counts are typically measured in AADF which is the Annual Ave... | 70,735 |
<p>When applying cross-validation to evaluate the predictive performance of a binary classification model, <strong>is it acceptable to separately sample from cases and non-cases to achieve class proportions in the training and testing partitions that closely match those in the original data set</strong>?</p>
<p>My app... | 42,396 |
<p>I have a sample of Chinese restaurant process which I want to model as Pitman–Yor process. How do I determine parameters of Pitman-Yor model from given sample?</p>
<p>For Dirichlet process I would just use the fact that on average K=αlogN where is K is observed number of tables and N is total number of visitors but... | 70,736 |
<p>I am a software developer looking to develop an alternative for the simple hypothesis testing scheme described <a href="http://stats.stackexchange.com/questions/38730/safely-determining-sample-size-for-a-b-testing">here</a>. In short, the test works as follows:</p>
<ul>
<li>Two URLs are compared for their ability t... | 70,737 |
<p>Lets assume I have a survival analysis study with an exposure, two covariates, and two time related variables. Say date of diagnosis and date of death. Combined, the two time related variables will be used to make a survival time variable: <code>t = date of death - date of diagnosis </code>.</p>
<p>The problem is t... | 70,738 |
<p>What relationship does a negative binomial regression have to heteroskedasticity and if one still needs to check and/or correct for it how would this be done?</p> | 70,739 |
<p>We (my team) are building a robot which will navigate around an arena.</p>
<p>The robot uses a camera to determine its position based on markers on the wall. We have tested this and found it can determine position well when close to the wall. However, at further distances, the markers appear to move randomly by sin... | 42,399 |
<p>I have seen it claimed in Hosmer & Lemeshow (and elsewhere) that least squares parameter estimation in logistic regression is suboptimal (does not lead to a minimum variance unbiased estimator). Does anyone know other books/articles that show/discuss this explicitly? Google and my personal library have not hel... | 31,839 |
<p>I am analyzing the influence of social capital on household income. I have collected data through a questionnaire survey for my study.Different dimensions (variables) of social capital were measured using 5-point multiple likert items.The scores on each item was summed up to obtain the single value for each variable... | 70,740 |
<p>My primary question is how to interpret the output (coefficients, F, P) when conducting a Type I (sequential) ANOVA? My specific research problem is a bit more complex, so I will break my example into parts. First, if I am interested in the effect of spider density (X1) on say plant growth (Y1) and I planted seedlin... | 70,741 |
<p>I'm working through an econometrics textbook and it's proving that </p>
<p>$$
\sigma^2 = E(\hat{\sigma}^2) = \frac{SSR}{n-2}
$$</p>
<p>I followed the proof (an example of which is shown on <a href="http://www.talkstats.com/showthread.php/9685-E-MSE-simple-linear-regression" rel="nofollow">talkstats</a>) until it r... | 31,840 |
<p>I checked different questions on similar topics, but none were exactly the answer I wanted and I am confused.</p>
<p>I am working with big data, the data has a bursty nature with high frequency. </p>
<p>I considered features one by one with respect to time (equivalent to one time-series) and want to remove outli... | 70,742 |
<p>I have a set of measurements $x_1$ ... $x_n$. These measurements are normally distributed, measuring the same value. However due to the way the data is measured, each $x$ has its own standard deviation: $s_1$ ... $s_n$. In other words I have a sensor which returns pairs (x,s).
Now, I wan to estimate parameters of di... | 70,743 |
<p>I'm trying to take a normal distribution of points, and force them to become a uniform distribution. I've had little success on <a href="http://stackoverflow.com/questions/3696747/generation-of-uniformly-distributed-random-noise">S.O.</a>, so I thought I'd ask here.</p>
<p>Basically, I have a hash function which ta... | 31,846 |
<p>Suppose I have some initial correlation matrix. I want to stress each correlation in the matrix by the same constant simultaneously (except the diagonal; lets call this global parallel stress since it affects the entire matrix by the same constant at the same time). I start with adding 0.01% to each correlation and ... | 31,848 |
<p>I am advising a small medical study (two groups, treatment is a dummy variable), i.e. a 2x2 contingency table. I'm comparing the value of the <a href="http://en.wikipedia.org/wiki/Pearson%27s_chi-square_test" rel="nofollow">Pearson's $\chi^2$ test</a> and a non parametric competitor <a href="http://en.wikipedia.org/... | 70,744 |
<p>The logic of multiple imputation (MI) is to impute the missing values not once but several (typically M=5) times, resulting in M completed datasets. The M completed datasets are then analyzed with complete-data methods upon which the M estimates and their standard errors are combined using Rubin's formulas to obtain... | 70,745 |
<p>Specifically the Welch's T-Test, but probably any T-Test, requires a value for Mean, Variance and N to be used to calculate the T-statistic and the degrees of freedom. I am concerned about these values if the sample has been bootstrapped (re-sampled with replacement) before using the T-Test. Specifically, I'm concer... | 70,746 |
<p>I performed a holdout cross-validation analysis on a multilevel model fit. The purpose of this was to show that we didn't have a problem with over-fitting, for which it worked just fine. Now we are writing it up for publication and I need a citation to support my methodology. I am looking for a good canonical statis... | 31,851 |
<p>I have three variables:</p>
<ul>
<li>distance (continuous, variable range negative infinity to positive infinity)</li>
<li>isLand (discrete categorical/ Boolean, variable range 1 or 0)</li>
<li>occupants (discrete categorical, variable range 0-7) </li>
</ul>
<p>I want to answer the following statistical questions... | 37,424 |
<p>I have a data set with high-dimensional feature space. Are there any pre-processing methodologies that can detect outliers from this data set? The outlier, I mean, are the ones that tend to be very different with other data points and can be the ones that generated by improper measurements.</p> | 70,747 |
<p>I'm trying to build a two class classifier on a dataset of around 570 samples. Im evaluating several classificiation stratigies (LDA, QDA,RDA, logistic, logistic with some additional ellements like splines ...) I have difficulties if I should take out a 25% of my 570 samples as a test set or if should just rely on 1... | 31,853 |
<p>A problem has recently arisen for me which involves estimating relative strength of various mechanisms contributing to an overall quantity. These strength parameters $q_j$, $j\in[M]$ stays fixed between observations of the quantity $\kappa_i$, $i\in[N]$, but the weighting factors $p_{ij}$ change between observations... | 70,748 |
<p>What would be the best option when you come across missing data. Do you exclude that person completely from the data analysis or not. If not then how do you go about it?</p>
<p>i have data on two groups at three different time points. At each time point they had to undertake a 6 minute walking test. Now some partic... | 70,749 |
<p>I'm pretty new in R, and I couldn't find any information about a package who can do the following: supposing that I have a set of data (for instance, different text documents), which can have several classes. </p>
<p>For example, a datum could be a Sport, a Sport with Ball, a Sport without Ball and a Car. I'd like ... | 31,854 |
<p>My book gives the following lemma: if $X_1, X_2, \dots, X_n$ are independent normally distributed random variables, such that each $X_i$ has mean $\mu$ and variance $\sigma^2$, then the mean of $\bar{x}$ is normally distributed with mean $\mu$ and variance $\sigma^2$ over $n$. </p>
<p>Following this, I attempted ... | 31,855 |
<p><strong>What is the best way to prepare interactions of categorical features before fitting with scikit-learn?</strong></p>
<p>With <code>statsmodels</code> I could conveniently say in R-style <code>smf.ols(formula = 'depvar ~ C(var1)*C(var2)', data=df).fit()</code> (same in Stata with <code>regress depvar i.var1##... | 70,750 |
<p>I have been examining the use of the Point Biserial correlation as a statistic to measure the relationship between a dichotomous variable and a continuous one. Wikipedia et. al. seem to concur that the Point Biserial Correlation is a special case of the Pearson Correlation, but I cannot find a proof for this, algebr... | 70,751 |
<p>I'm dealing with a large p small n problem (p>1000, n=150) and have decided to use glmnet and lars to select possible explanatory variables (as I understand <em>is</em> their functionality) rather than do this manually.</p>
<p>I have gotten out both a lars, and a glmnet object from the functions, but now can't disc... | 70,752 |
<p>Apologies in advance if this is very basic; I am quite new to statistics.</p>
<p>I have a large set of 7 dimensional data, for two groups.</p>
<p>In my example, they are express relative preferences over a certain bundle of goods (for men, and for women). (Weightings of the parameters in a representative utility f... | 31,858 |
<p>Not sure if this should be in Stack Exchange or here, but here goes.</p>
<p>I have a linear mixed model in SPSS, and I want the confidence intervals for slopes of the continuous*categorical interactions. Below is the output from the analysis, with estimates of fixed effects and the estimated marginal means. I want ... | 70,753 |
<p>Suppose we have a sequence of items, from an alphabet of 2: {0,1}. For example, this 8-bit sequence: 10001010</p>
<p>You generate a random 8-bit string. The probability of you matching the first bit is $1/2$ or 50%, the last bit also $1/2$ or 50%, and of matching both: $1/2 * 1/2$ or 25%. </p>
<p>Part 1 concerns... | 31,859 |
<p>I am using the following equations for Kalman filter. The state vector is $x$ and observations are $z$. Both $x$ and $z$ are multivariate vectors of same length.</p>
<p>Forecast model: $x_{t+1} = 0.963 x_t + \mathcal{N}(2.19,3.34)$</p>
<p>Observation model: $z_t = -0.00542849 x_t + \mathcal{N}(0.4524,0.038952)$</p... | 27,888 |
<p>I would like to use another type of data, not atomic data, as a feature for a prediction.
Suppose I have a Table with those Features:
- Column 1: Categorical - House
- Column 2: Numerical - 23.22
- Column 3: A Vector - [ 12, 22, 32 ]
- Column 4: A Tree - [ [ 2323, 2323 ],[2323, 2323] , [ Boolean, Categorical ] ]
- ... | 70,754 |
<p>I'm working with a data set with 2-3 response variables and 7 predictor variables. All the variables are categorical. If there were just one response variable, I think a multinomial logit would be the right model, but there are 2 or 3. So my question is - is there a multivariate version of the multinomial logit?</p>... | 31,862 |
<p>Is there a use of using a Randomized Block design when you only have one treatment and you only want to test the effects of this single treatment?</p>
<p>The experiment in question is to see whether a training exercise (the treatment) effects the grades of a number of students. Students are grouped in a control and... | 70,755 |
<p>I have used the custom tables feature in SPSS for my job almost every day. I am trying to learn R . How can I recreate the custom tables functionality in R. Is there some specific package that I need to use?</p> | 70,756 |
<p>I have two logistic regression models in R made with <code>glm()</code>. They both use the same variables, but were made using different subsets of a matrix. Is there an easy way to get an average model which gives the means of the coefficients and then use this with the predict() function?</p>
<p>[ sorry if this... | 70,757 |
<p>When I was performing a PCA on a large data set, I only get the PC1 explaining about 25% of variance and PC2 about 20%, PC3 about 15%, PC4 about 10%... So I wonder if there is a way to increase the Proportion of Variance Explained in PCA.</p> | 70,758 |
<p>I am going to study about big data use cases in the real world. I want the stuff to be preferable in book format(not article or blog posts or website articles) and high level, industry based and vendor neutral. Up to now I came to this cases which are concise books up to 100 pages that describe how Industry can solv... | 70,759 |
<p>In SPSS, if I use the hierarchical clustering procedure, I have the ability to cluster both variables and cases using a variety of methods and distance measures. For this task, I would like to use R to cluster my variables.</p>
<p>For context, my data come from a survey and the respondents were able to select mult... | 70,760 |
<p><img src="http://i.stack.imgur.com/GTB1c.png" alt="enter image description here"></p>
<p>This is a Minitab printout. I want to find the value of A5, or S. </p>
<p>I think S is supposed to be the sample standard deviation, but I don't know how to calculate it. Any tips on how I should go about calculating it?</p> | 70,761 |
<p>What steps could be taken to check for bivariate Gaussianity without using regression based check? Can we somehow employ the use of definition of <a href="http://en.wikipedia.org/wiki/Variogram">variogram</a> measure for assessing spatial variability?</p> | 31,864 |
<p>I'm trying to convert a bunch of Stata commands to their R equivalents, and I'm struggling with how R does handle confidence intervals for inferential statistics of single variables.</p>
<p>In Stata, I can use <code>ci variable</code> to calculate normal confidence intervals, <code>ci variable, b</code> to calculat... | 31,866 |
<p>I have data that is, at its most basic level, activity counts per minute of fruit flies. Flies are considered to be asleep when they have no activity for at least 5 minutes. The data essentially looks somewhat like a sinusoidal curve when plotted as activity vs. time or sleep vs. time. I have researched various norm... | 62 |
<p>Suppose I have a set of $k$ matrices.</p>
<p>$$
\mathbb D = A_1,A_2,...,A_k
$$</p>
<p>Each column of $A$ is categorical vector.</p>
<p>$$
A = v_1,v_2,...,v_n
$$</p>
<p>I want to find the mapping
$$
f: A \rightarrow Q
$$
Where $Q$ is a $(n,n)$ matrix such that </p>
<p>$$
\frac{1}{k} \sum_k \text... | 70,762 |
<p>I am estimating the effect of $x$ on $y$; $y$ and $x$ are available both by city and by year. During the first period, $T_1$, both $x$ and $y$ generally increase. During the second period, $T_2$, both generally decrease. I have about 30 cities over 40 years.</p>
<ol>
<li><p>How can I use regression to attribute... | 31,868 |
<p>I'm not sure what this is called but I remember seeing a colleague of mine doing a multivariate regression much like</p>
<p>$$Y \sim X_1 + X_2 + X_3$$</p>
<p>and then he said he would "orthogonalize" so he regressed each of the IVs against the other ones, and took the residuals..as in:</p>
<p>$$Z_1 = residuals(X_... | 31,869 |
<p><img src="http://i.stack.imgur.com/kKvo3.jpg" alt="enter image description here"></p>
<p>I'm trying to understand the neural networks with a given example. On the graph, observed instances are shown. It states that the function is symmetric around x=3.5.</p>
<p>So the question is : How would you modify the error f... | 70,763 |
<p>I am very interested in learning how to create reoccurring reports from my R code and ggplot2 visualization.</p>
<p>I understand that LaTeX seems to be a possible answer, and to use it with R most use Sweave. And for presentations from R to LaTeX people use Beamer.</p>
<p>My question is, what I should learn first,... | 70,764 |
<p>There are words from "The Elements of Statistical Learning" on page 91:</p>
<blockquote>
<p>The K centroids in p-dimensional input space span at most K-1 dimensional subspace, and if p
is much larger than K, this will be a considerable drop in dimension.</p>
</blockquote>
<p>I have two questions:</p>
<ol>
<l... | 70,765 |
<p>I want to do a CART analysis with <strong>multiple dependent variables.</strong> Which program is able to do that?</p> | 70,766 |
<p>I calculate Beta risk for multiple assets by running multiple regressions:
Return = intercept + Beta*Market_Return</p>
<p>Then I want to compare the Betas. I run other regression where Beta is dependent variable against several independent variables:
Beta = intercept + X + Y...</p>
<p>May I include R squared from... | 70,767 |
<p>Suppose we have data set $X$ with $20$ observations. A confidence interval for the mean $\mu$ is always the same no matter what hypothesis we test? So if we test $H_a: \mu < \mu_0$, $H_a: \mu \neq \mu_0$ or $H_a: \mu > \mu_0$, the confidence interval will be the same?</p> | 12,157 |
<p>I have just conducted an experiment in which I have measured glucose concentration in patients (4 different treatment groups) at 3 different weeks ( pre, 6 weeks and 12 weeks). I want to use Mixed Anova to test if there is any significant difference between treatments in glucose concentration (also possible time and... | 70,768 |
<p>I am trying to perform a z-test with a brain-imaging software. I was told that the best way was to use a general linear model with one subject in one group and the rest in the other group. Using this method gives results that look identical to calculating the average and standard deviation of the control group and p... | 31,874 |
<p>All the interpretations I've seen have referred instead to the odds being 3 times higher in Group X. However, It is not clear to me that there is a meaningful difference between these formulations. </p>
<p>Edit: In thinking that it was OK to express things in this way, I was influenced by <a href="http://sphweb.bum... | 30,430 |
<p>I am seeing some thing very strange when I do an ANOVA in R. The actual data doesn't matter here, check this out - </p>
<blockquote>
<p>summary(aov(t(freq)~t(mob)+t(tab)+t(comp)))</p>
</blockquote>
<p>and the F value is 4.4% for the comp variable, and >50% for the other two.</p>
<p>It seems from the F value th... | 70,769 |
<p>I am comparing the distrubution of different groups using the violin plots, however most of the online resources I found are just related to how to make the plots and very basic interpretation of the results (the median variation, the data is clustered or not).</p>
<p>I am looking for detailed examples that I can f... | 70,770 |
<p>If I have derived parameter estimates for a distribution for some data, do I need to conduct a significance test on these to determine how valid they are? Or is the same effect done by just performing a goodness-of-fit test for the distribution?</p> | 70,771 |
<p>Can somebody illustrate, as Greg does, but in more detail, how random variables can be dependent but have zero covariance? Greg, a poster here, gives an example using a circle <a href="http://stats.stackexchange.com/questions/12842/covariance-and-independence/12898#12898">here</a>. </p>
<p>Can somebody explain this... | 49,340 |
<p>I have variables of the following kind (coded in R):</p>
<pre><code>set.seed(2)
dependent.variable = rnorm(12)
exp1 = c(1,3,4,8,3,4,1,5,6,6,7,9)
exp2 = c(1,3,6,2,1,1,3,4,6,4,1,1)
exp3 = exp1*exp2
</code></pre>
<p>my three explanatory variables are related by an equation of the kind: $exp1 = \frac{exp3}{exp2}$. For... | 70,772 |
<p>I tried to do a CFA with the <code>lavaan</code> package in R.
Here is my model:</p>
<p><img src="http://i.stack.imgur.com/f1w70.jpg" alt="enter image description here"></p>
<p>I know how to define my latent variables like this:</p>
<pre><code>MASTER.model <- ' Usability =~ PUS1 + PUS2 + PUS3 + PUS4 + PUS5
... | 70,773 |
<p>Can somebody tell me how to visualize multidimension array? Regarding two dimensional array, I don't have any trouble. But, when it comes to case of 3-D or many, then I start having problem. I tried to visualize using parallel coordinate. I am unable to understand even parallel coordinates. I will be glad if someone... | 31,882 |
<p><strong>Background:</strong> I am working on the problem of classifying objects found in some biological images. Time and again, we encounter objects which do not fall into any of the categories/classes we are interested in and we would like to filter out these uninteresting objects before analyzing the interesting ... | 31,883 |
<p>I've been following the R code from page 74 of <a href="http://courses.nus.edu.sg/course/stacar/internet/st3242/handouts/notes3.pdf" rel="nofollow">this link</a> to plot a survival curve given a set of independent variable values. Note that the author uses</p>
<pre><code> phm = coxph(Surv(t,delta)~x)
... | 31,884 |
<p>I want to generate a forest using <a href="http://en.wikipedia.org/wiki/C4.5_algorithm" rel="nofollow">C4.5 trees</a>, (the <a href="http://cran.r-project.org/web/packages/randomForest/randomForest.pdf" rel="nofollow">randomForest Package</a> generates them using CART) Any suggestions on packages and commands in R?<... | 70,774 |
<p>Can anyone show me what is the difference between coupled HMM's viterbi algorithm and tranditional HMM's viterbi algorithm? Is there any examples?</p> | 70,775 |
<p>Somebody asked me this question in a job interview and I replied that their joint distribution is always Gaussian. I thought that I can always write a bivariate Gaussian with their means and variance and covariances. I am wondering if there can be a case for which the joint probability of two Gaussians is not Gaussi... | 49,459 |
<p>I have a large survey sample. </p>
<p>I have a question like "What is your level of satisfaction with ...". It should be my outcome variable.</p>
<p>Each respondent can give a unique answer of one of this possibilities: </p>
<pre><code>1. Very Good 2. Good 3. Bad 4. Very Bad 5. Don't know
</code></pre... | 31,886 |
<p>I am dealing with a classification problem with 10 classes. More or less, the number of samples per class is same. Yet I am getting a skewed classification result. By changing the gamma value in the Gaussian kernel SVM, the samples are getting classified to one particular class in most cases. That is, when the gamm... | 70,776 |
<p>I have 6000 sets of ~350 items each, all from the pool of ~13800 items total. Items in each set do not repeat. I want to find rules like "if 1398 is present, 1035 will most likely be present too". I've tried FPGrowth and Eclat, but the problem is, not every set has these combinations, so their support is low and the... | 12,164 |
<p>This is related to another <a href="http://stats.stackexchange.com/questions/4175/resampling-binomial-z-and-t-test-help-with-real-data">question</a> I asked recently. To recap:</p>
<p>[<em>I had 30 people call a number and then roll a 5 sided die. If the call matches the subsequent face then the trial is a hit, els... | 42,478 |
<p>I recently came across multidimensional scaling. I am trying to understand this tool better and its role in modern statistics. So here are a few guiding questions:</p>
<ul>
<li>Which questions does it answer?</li>
<li>Which researchers are often interested in using it?</li>
<li>Are there other statistical techniqu... | 70,777 |
<p>The context of this question is within a health framework i.e. looking at one or more therapies in the treatment of a condition.
It appears that even well respected researchers confuse the terms <strong>efficacy</strong> and <strong>effectiveness</strong>, using the terms interchangeably. </p>
<ul>
<li>How can one ... | 42,480 |
<p>Usually online clustering methods (based on kmeans or not) define a distance threshold value. If a new data-point $x$ is far enough from the nearest center $c$ (i.e. the distance from $x$ to $c$ is greater than the threshold), then just give this $x$ its own new cluster.</p>
<p>I saw that many methods theoretically... | 70,778 |
<p>I know that the beta distribution is conjugate to the binomial. But what is the conjugate prior of the beta? Thank you.</p> | 70,779 |
<p>We are running a study which investigates platelet aggregation changes during three trimesters of pregnancy and postnatal period. </p>
<p>Then we compare each of these phases to control non-pregnant women. </p>
<p>The sample size is 46 including 10 per each trimester, 10 postnatal and 6 as control. </p>
<p>The ca... | 31,894 |
<p>Suppose that my application's users are asked to give their opinion about the probability that a statement is true. They are presented with a slider widget that goes from 0% to 100%, but let's say the slider goes from 0 to 1. Due to the discrete nature of computing, there are a finite number of possibilities for the... | 28 |
<p>Suppose the experimenters are interested in how weight gain in rats is affected by different sources of protein: <code>Beef</code>, <code>Cereal</code> and <code>Egg</code>. </p>
<p>Suppose there are $30$ heterogeneous rats in terms of initial weight and there are two groups of rats identified prior to the experime... | 70,780 |
<p>I am not sure about this plot if it looks good as the dots appear around the line. So I just want to ask if it looks okay. My data is quite large (almost 3000 observations) and maybe that is why it looks like this.</p>
<p><img src="http://i.stack.imgur.com/4lEeh.jpg" alt="enter image description here"></p> | 70,781 |
<p>I am somewhat new to data mining, and I am working on a classification model for movie rating prediction. </p>
<p>I have collected data sets from IMDB, and I am planning to use a decision trees and nearest neighbor approaches for my model. I would like to know which freely available data mining tool could provide t... | 70,782 |
<p><em>Question (a)</em></p>
<p>Random walk on a clock. Consider the numbers $1, 2, \dots, 12$ written around a clock. Consider a Markov chain that jumps with equal probability to one of the two adjacent numbers each step. </p>
<ul>
<li>What is the expected number of steps that $X_n$ will will take to return to its s... | 47,048 |
<p>I must implement some Chi Square Test to test the randomness of "my" implementation, but I can't understand what this tests really say.</p>
<p>The tests are different but what I always do is: divide in different categories, calculate the probability to fall in these categories and then calculate this number:</p>
<... | 30,433 |
<p>I am conducting a survey where I ask respondents to rate five factors on a scale from 1 to 100 on how much the factor affects an individual's perception of the value of a particular product.</p>
<p>How can I determine whether the valuation of the product is standard or not standard across respondents?</p> | 70,783 |
<p>A bank classifies loans as paid in full (F), in good standing (G), in arrears (A), or as a bad debt (B). Loans move between the categories according to the following transition probability:</p>
<p>$$B = \begin{pmatrix}1.0000 & 0 & 0 & 0 \\\ 0.1000 & 0.8000 & 0.1000 & 0 \\\ 0.1000 & 0.400... | 37,441 |
<p>I have 2 classifiers with different scales. How can I adjust one classifier to the scale of the other without loss of quality? </p>
<p>On the scatter plot we have <a href="http://i55.tinypic.com/2v0fm28.png" rel="nofollow">2 solutions plotted (x1, x2) against each other</a>. I believe using linear combination as a ... | 121 |
<p>I am running exploratory factor analysis and have extracted 3 factors, with items clearly loading on each one.<br>
However, it appears to me that the items that have loaded onto the first factor could be further split into two, theoretically meaningful, groups. My question is therefore, could I re-run factor analysi... | 70,784 |
<p>I've been studying hierachial reinforcement learning problems, and while a lot of papers propose algorithms for learning a policy, they all seem to assume they know in advance a graph structure describing the hierarchy of the actions in the domain. For example, <a href="http://citeseerx.ist.psu.edu/viewdoc/download?... | 31,900 |
<p>How do you tell if the correlations at different lags obtained from the cross-correlation (ccf function) of two time series are significant. </p> | 49,323 |
<p>I'm curious to know if anyone has a specific reference (text or journal article) to support the common practice in the medical literature of performing sample size calculation using methods that are parametric (i.e. assuming a normal distribution and a certain variance of measurements) when the analysis of the prima... | 31,901 |
<p>I am using the epitools in R for calculating the confidence interval of relative risk.</p>
<p><a href="http://bm2.genes.nig.ac.jp/RGM2/R_current/library/epitools/man/riskratio.html" rel="nofollow">http://bm2.genes.nig.ac.jp/RGM2/R_current/library/epitools/man/riskratio.html</a></p>
<p>There are three methods insid... | 70,785 |
<p><br>
I would be very grateful if anybody has some suggestion about how to deal with the statistics of the following experiment.<br>
I am planning to study soil characteristics under different trees in soil of different ages in two different countries.
I am going to have 2 different tree types, 4 age classes and for ... | 70,786 |
<p>If I want to perform bagging, would subsamples with sizes of 0.1% of the actual data be appropriate?</p>
<p>The reason I want to do so is because my actual data set is very large in the tens of millions.</p> | 70,787 |
<p>I have question regarding GARCH (i.e. ARMA-GARCH) estimation and year dummies. We want to estimate a GARCH model for a time series constructed of different December contracts. We choose december contracts since these are the most relevant contracts for hedging grains. So we do not have a continuous log returns serie... | 70,788 |
<p>I do not think that this is a difficult question, but I guess someone needs experience to answer it. It is a question that is asked a lot here, but I did not found any answer that explains the reasons of choosing an appropriate ML algorithm.</p>
<p>So, let's suppose we have a set of data. And let's suppose I want t... | 70,789 |
<p>I am running a PCA for quality in a water resource. I have 15 original variables. Running the PCA using Minitab, it turned out that the first PC is responsible for 99.7% of the variation. Looking at the eigenvectors, all the original values have almost the same correlation value with PC1 (about 0.25). What does that... | 36,496 |
<p>I have found extensive literature proposing all sorts of criteria (e.g. <a href="http://vohweb.chem.ucla.edu/voh/classes%5Cwinter08%5C160BID48%5CNumClusters.pdf">Glenn et al. 1985</a>(pdf) and <a href="http://www.cc.gatech.edu/~hpark/papers/cluster_JOGO.pdf">Jung et al. 2002</a>(pdf)). However, most of these are not... | 18,267 |
<p>I conducted a Bayesian analysis in winbugs and then checked the convergence from the history plots. The regression coefficients look stabilized, but the variance parameters don't. I got the number of iteration up to 5000, but it still does not look stabilized. I attached the history plots of a regression coefficient... | 70,790 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.