question stringlengths 37 38.8k | group_id int64 0 74.5k |
|---|---|
<p>Let's say I have two people. Each of whom I create a network matrix for daily for some of their daily habits $(i.e. A, B, C, D)$. I do this for, let's say $60$ days. </p>
<p><img src="http://www.chrisjvargo.com/Matrix%20Time%20Series.png" alt="Two People and their daily matrices"></p>
<p>I didn't bother to change ... | 72,623 |
<p>Sorry to ask such a blunt question, but I'm running out of time and I just can't figure this seemingly simple thing out. It's the p-value for $B_0$, a single variable regression. $H_0: B_0=0$ and $H_1: B0 \neq 0$. $T_{calc} = (0.5681 - 0)/0.9284 = 0.6119$. Then it says $p\text{-value}=2 \cdot (t\ge 0,6119) =2 \cdot ... | 72,624 |
<p>I am wondering what is the best way to forecast the business cycle based on the past. Currently I feed the seasonally-adjusted GDP index data to a Hodrick–Prescott filter, extract the cyclical component, take the last data point, find the similar points in the past and see what happened afterwards. (See attached pic... | 34,613 |
<p>this is a conceptual question. In data mining, the problem often arises that scientists/data engineers are using an expert guess for the underlying distribution of their data. Often their assumption is based on previous results of academic research and does not really reflect the real distribution of the dataset. </... | 34,614 |
<p>For 86 companies and for 103 days, I have collected (i) tweets (variable <code>hbVol</code>) about each company and (ii) pageviews for the corporate wikipedia page (<code>wikiVol</code>). The dependent variable is each company's stock trading volume (<code>stockVol0</code>). My data is structured as follows:</p>
<p... | 72,625 |
<p>I am trying to figure out what the right statistical test to use is for data where the DV is continuous, and the IV's are categorical. There are a lot of different DV's that I want to run through a model one at a time, so I am having a hard time figuring out how to do exploratory statistics to really figure out the ... | 72,626 |
<p>I'm using multinomial logistic regression analysis to analyse deer behavioural responses to camera traps based on 7 predictor variables. </p>
<p>I have 2 models which are very close together in AIC value (season AIC 1005.103; season and percentage cover 1005.023). Season and percentage cover is the best model (but ... | 72,627 |
<p>for a project I need to extract values from customers yearly heat costs bill.
The customer takes a photo of the bill and the program should extract the values heating period of the billing, type of energy source (gas, fuel etc.) and the amount of energy used.
I have little knowledge of machine learning (one lecture ... | 72,628 |
<p>I'm modeling (using GLM) one binary explanatory variable against a binary response variable.</p>
<p>The output looks ok to me, but I'm a biologist with a basic knowledge of stats, I just wanted to ask if there's any rule/caveat/problem for modeling a binary versus a binary?</p> | 72,629 |
<p>Imagine an a la carte buffet with n different rooms. On entering the buffet you pick a room (let's say American, Mexican or Italian food) where you stay for the duration of your visit.</p>
<p>Once in a room, you have a full selection of small dishes to pick from and most people choose multiples of several different... | 34,618 |
<p>I am given two time series of prices between 2009 and 2013. Price series A is weekly data, series B is monthly data. I would like to compare some basic descriptive statistics of these two time series data (such as mean, standard deviation etc).</p>
<p>Intuitively, I just wonder if the period sampling difference sho... | 12,582 |
<p>A normal ANOVA model always needs a categorical variable as a predictor(the factor/group) right? Please let me know the reason if you think otherwise.</p>
<p>So in case of a linear regression with only continuous predictors, how can the ANOVA table be even used since ANOVA requires at least 1 categorical variable a... | 34,619 |
<p>I need to analyze a data-set, with a very messy design, I am not sure how. I will try to make it simple. A new kind of stitches was invented, and is tested vs. 2 old kind of stitches. I will call this: Treatment, control 1 and control 2.</p>
<p>A few patients were selected, needing stitches. Each patient was assign... | 34,620 |
<p>Good Day, I believe this issue is more of a lack of understand of R (as I have never used it till recently) than anything else. What I am looking for is references, or documents to help me solve my problem.</p>
<p>I have a set of data that I created a pair of decision tress on (pruned and unpruned). I did this u... | 45,801 |
<p>$$Y \sim Geometric(P)\\
P \sim \mathcal B(2, 1)$$</p>
<p>I'm trying to compute $E[Y]$ without finding marginal distribution of $Y$. I need some hints here. I also need to find the pmf of $Y$. My approach is as follows: </p>
<p>Integrate from 0, 1 over $p: f(p)(1-f(p))^{(y-1)}$ where $f(p)$ is the pdf of $\mat... | 72,630 |
<p>I recently started taking Probabilistic Graphical Models on coursera, and 2 weeks after starting I am starting to believe I am not that great in Probability and as a result of that I am not even able to follow the first topic (Bayesian Network). That being said I want to make an effort to learn this course, so can y... | 72,631 |
<p>I have a question about a simulation set up. Assume there are two groups (Z = 0 and Z = 1). The outcome for Z = 0 and Z = 1 are generated by the following equations:</p>
<p>$Y_0 = \alpha_0 + \beta_{01}*{x_1} + \beta_{02}*{x_2} + \epsilon_{0}$</p>
<p>$Y_1 = \alpha_1 + \beta_{11}*{x_1} + \beta_{12}*{x_2} + \epsilon_... | 72,632 |
<p>I have been calculating p-values for correlations using bootstrapping. I've just been using the same p-value cutoff regardless of the number of pair-wise calculations. Intuitively, it seems to me that the more correlations that I perform, the more likely I am to obtain a spurious correlation due to random chance.</p... | 72,633 |
<p>I'm trying to learn the Bayesian network structure from a very large data set, and the R package I used for learning can only handle a very small portion of the data set (~10%) at one time due to the computational limitations. </p>
<p>The conventional k-fold cross-validation strategy uses k-1 subsets for training a... | 72,634 |
<p>After attempting to produce a linear mixed model I was left with a great deal of heterogeneity.</p>
<pre><code>lme1 <- lme(Average.payoff ~ Game + Type + Others.Type + Game:Type +
Game:Others.Type + Type:Others.Type, random=~1|Subjects, method="REML",
data=Subjectsm1)
</code></pre>
<p>The response term <c... | 72,635 |
<p>I have a large set of data for 37 different clinical units (all oncology) in their respective 37 hospitals. There are two specific outcome variables that I need to analyse:</p>
<p>First, drug usage for specific drugs types and classes (aggregated drugs) that are expressed as a rate – DDD (Defined Daily Doses) per ... | 39,844 |
<p>I'm not a statistics expert, so I'm hoping someone here can lend me a hand.</p>
<p>I've got a bunch of key-value pairs associated with a specific time range. Something like this:</p>
<pre><code><time>|<key>|<value>
0 |1 |34534
0 |2 |23434
0 |3 |4606
1 |1 |945954
1 ... | 72,636 |
<p>I would like some advice on how to interpret parameter estimates with a continuous dependent variable (healthy food consumption) and a 6-category predictor (income, from 1 = lowest income to<br>
6 = highest income band in GLM.
My output is as follows: </p>
<p>Parameter Estimates<br>
Dependent Variable: Healthy </p... | 72,637 |
<p>I am building a prediction model based on SVM model with RBF kernel. The training samples represent features obtained from genome regions (called binding sites) that are targeted (regulated) by proteins. The model will learn to distinguish between regions targeted by proteins and regions that are not. (I created pos... | 34,632 |
<p>I have a times series for temperature and I am trying to decompose it into a </p>
<p>seasonal + trend + stochastic process</p>
<p>to look at what model would fit for the stochastic process.</p>
<p>However, I only have data for 333 days, and I assume my data should include a periodic phenomena, with the period bei... | 72,638 |
<p>I have two series of information about (for example) the amount of cars on a two roads over a 1 mile stretch. I have collected 4 outcomes: Number of cars passing through an intersection at 1, 10, and 60 minutes as well as greatest number of cars in the area in the last hour.</p>
<p>I'd like to model the maximum of ... | 72,639 |
<p>This should probably be easy, but I don't see yet how to prove it.</p>
<p>Given is that $y=X_1\beta_1 + X_2 \beta_2 + \epsilon$. It holds that $X=\begin{pmatrix} X_1 & X_2 \end{pmatrix}$. Furthermore, it is given that $X_2'X_2=cX_1'X_1$.
Now show using the formula $\operatorname{Var}(X'X)^{-1}=\sigma^2 V$, wher... | 72,640 |
<p>I have the dataset that contains one continuous measure of plant leafs (PC1 scores of individual leafs), that is dependent variable and three others that I need to use as independant, explanatory. One is every leaf area, other is the individual and the third is the leaf number in sequence for individual. As every in... | 72,641 |
<p>I have made a survey to weight the importance of different features of a credit card using a 5 point Likert scale with scores (very important = 5...neither important or unimportant = 1). I have 8 criterions, each having a similar question, such as the one below:</p>
<p>How important is the cash back feature on a cr... | 72,642 |
<p>I'm using python's sklearn for multi-class classification (SVC)
When using the predict method, i get very high scores with my dataset,
However, I want to plot ROC curves for each of my classes. That is, I would like to reduce the problem to a in_class/out_of_class problem for each of the classes.
For that i resorted... | 72,643 |
<p>I am looking for an empirical paper that perform a difference-in-difference regression where the whole did regression (treated+post+post*treated) is interacted with a continuous variable (or a categorical one)... Do you have an idea of such a paper ? </p> | 72,644 |
<p>I am trying to fit a distribution function to empirical observations that have the following properties:</p>
<ol>
<li>Non-zero mean</li>
<li>Non-unit variance</li>
<li>Heavy tails</li>
<li>Asymmetric about the mode</li>
</ol>
<p>I am considering performing this task by fitting a non-central, generalized t-distribu... | 34,636 |
<p>My current model is:</p>
<blockquote>
<p>$$y_i = a_0 +a_1x_i + a_2x_i^2 + \epsilon_i $$</p>
</blockquote>
<p>With $E[\epsilon_i] = 0, Var[\epsilon_i] = \sigma^2$.</p>
<p>I have the information:</p>
<blockquote>
<p>$$\begin{matrix} i & \mathrm{Response} \, y_i & \mathrm{Covariate} \, x_i \\ 1 & -1... | 45,820 |
<p>I'd like to determine the relative importance of sets of variables toward a <code>randomForest</code> classification model in R. The <code>importance</code> function provides the <code>MeanDecreaseGini</code> metric for each individual predictor--is it as simple as summing this across each predictor in a set?</p>
<... | 72,645 |
<p>I am attempting to analyze biological data, to see whether the number of events in a given time interval is more/less than expected based on the overall frequency. How would one approach this? </p>
<p>An example of how I would frame this:
Out of 100 ms, 16/44 events occur in 15 ms, and 28/44 events occur in the rem... | 72,646 |
<p>What parameters should one <strong>pre-specify</strong> before designing/running an experiment? (e.g. a two-sample, one-side, t-test)</p>
<p>My understanding is that on establishes: </p>
<ol>
<li>Null hypothesis</li>
<li><strong>Maximum</strong> Significance level</li>
<li><strong>Minimum</strong> Power</li>
<li><... | 72,647 |
<p>I ran an experiment with two factors each with two levels, 5 replicates each combination and one response variable. My data are non-normal and heterocedastic. Transformations didn't help. I ran a permutation ANOVA (<code>aovp - package lmperm - R</code>), but I am not sure this is the right way to go and I don't kno... | 72,648 |
<p>I have produced generalized additive models for deforestation. To account for spatial-autocorrelation, I have included latitude and longitude as a smoothed, interaction term (i.e. s(x,y)).</p>
<p>I've based this on reading many papers where the authors say 'to account for spatial autocorrelation, coordinates of poi... | 49,903 |
<p>Lets say I need to rank the "strength" of a bunch of objects based on a number of factors, as far as I can tell, there are two ways people seem to commonly do this :</p>
<p>(a) calculate normalised scores (i.e. factor-avg(factor)/stddev(factor)), then sum the individual normalised results for each factor and rank t... | 72,649 |
<p>Suppose I've a set of information, </p>
<blockquote>
<pre><code>id t s x H0 h0 H0i Hi Di Eu Elu
1 2 1 53 0.01067033 0.01067033 0.01371871 0.01371871 2 1.039715 0.029300175
2 4 0 60 0.02148908 0.01081875 0.02856059 0.04227930 1 1.019138 0.009121439
3 5 ... | 34,643 |
<p>It is well-known that as you have more evidence (say in the form of larger $n$ for $n$ i.i.d. examples), the Bayesian prior gets "forgotten", and most of the inference is impacted by the evidence (or the likelihood).</p>
<p>It is easy to see it for various specific case (such as Bernoulli with Beta prior or other t... | 34,644 |
<p>I am training a SVM classifier based on a given document collections. I started from using 500 documents for training, then I add another 500 for training, and so on. In other words, I have three training sets, 500, 1000, 1500. And the smaller training set is a subset of the sequential larger set. I validate the mod... | 72,650 |
<p>I know that $\beta$ (type II error) is the probability that the null hypothesis is false, but it is not rejected. The power of the test is defined $1−β$. I still thought that the power of the test is important only in the case when $H_0$ is not rejected. However my statistical software compute the power of the test ... | 72,651 |
<p>Two friends and I have been playing a game that is a combination of skill and luck. (as most games are). We assume that if the game was all luck and/or we all had the same skill level eventually the win% of all of us would approach 33%.</p>
<p>So what sample size would we need to show that one of us was "better" a... | 34,646 |
<p>I have the following scenario:</p>
<p>Let $X_i$ denote some event. Now I have the following calculated probabilities.</p>
<p>$P(X_1 \cap X_2 \cap \cdots \cap X_9 | X_{10})$</p>
<p>$P(X_1 \cap X_2 \cap \cdots \cap X_{8} \cap X_{10} | X_{9})$</p>
<p>$\vdots$</p>
<p>$P(X_2 \cap \cdots \cap X_{9} \cap X_{10} | X_{1... | 72,652 |
<p>I have a dataset (time series data) of measured signal power values from a radio receiver. The data does not originate from a controlled experiment. I have limited knowledge of the underlying processes and distributions.</p>
<p>My observations are the result of one or more processes. In any case, there is a backgro... | 72,653 |
<p>Is using a 2 way MANOVA to check whether height and weight differ across age groups and gender, the same as using a 2 way ANOVA to check whether BMI (wt in kg/ht in m$^2$) differ across age groups and gender?</p> | 34,647 |
<p>For an ARIMA (0,0,1) model, I understand that R follows the equation:
xt = mu + e(t) + theta*e(t-1)
(Please correct me if I am wrong)</p>
<p>I assume e(t-1) is same as the residual of the last observation. But how is e(t) calculated?</p>
<p>For example, here are the first four observations in a sample data:
526 6... | 49,904 |
<p>I have two classifiers built with the same data. How can I measure divergence of these models?</p>
<p>I found something like <a href="http://en.wikipedia.org/wiki/Deviance_information_criterion" rel="nofollow">DIC</a> but I don't know how to calculate this in R?</p> | 34,648 |
<p>I have a nominal variable and a continuous (interval) variable. SPSS crosstab includes an option for Eta. Is it appropriate to use eta to test effect of the binary nominal variable on the continuous variable? How would I interpret the result such as Eta = 0.04? Thanks.</p> | 72,654 |
<p>I have values that are not normally distributed since most (132) of the (140) values are 0 or 1. There are a few that are <10, one about 80 and one about 650. Is it valid to use a normal Q-Q plot to identify the outliers?</p> | 34,649 |
<p>We're designing a survey where we ask students to indicate their level of agreement (likert scale 1 - Strongly agree....5 - Strongly disagree. We ran factor analysis on the data and obtained 4 factors. In order to get composite scores for each factor, this is what we did:
For example,
If factor 1 was made up of 3... | 72,655 |
<p>I have fitted random coefficient Poisson analysis in R. I have obtained the following results: </p>
<p>Generalized linear mixed model fit by maximum likelihood ['glmerMod']
Family: poisson ( log )</p>
<p>Formula: frequency ~ 1 + cc + ageveh + make + (1 | AREA) </p>
<p>Data: x </p>
<pre><code> AIC BIC l... | 72,656 |
<p>Is there any specific algorithm for online handwriting recognition?
The algorithm should recognize non-cursive and cursive handwriting.</p>
<p>I know there is already a similar post on <a href="http://stackoverflow.com/questions/1206284/algorithm-for-hand-writing-recognition">stackoverflow.com</a>, but it was post... | 72,657 |
<p>So one day after a tasty dinner full of bananas, an idea comes to your mind (you are person A) - "What if eating bananas can cure cancer?". Being a scientist at heart, you conduct a double blind study and your data shows you that bananas cure cancer with probability at least 99.99%. "WOW!" - you think, - "I am onto ... | 34,651 |
<p>Here's a real basic question. I'm trying to teach myself a bit of stats with Verzani's Using R for Introductory Statistics.</p>
<p>In question 5.13 he asks: A sample of 100 people is drawn from a population of 600,000. If it is known that 40% of the population has a specific attribute, what is the probability that ... | 37,989 |
<p>I work on a couple of library websites and we want to know who are users are so we can make decisions about how to design the site and focus efforts.</p>
<p>These are the classes of users we are interested in:</p>
<p>"Please select the answer that best describes yourself:"</p>
<ul>
<li>k12-teacher-librarian</li>
... | 72,658 |
<p>It is quite easy to prove that if $p(\theta)$ is a conjugate prior to some likelihood then the following:</p>
<p>$$q(\theta') \propto p(\theta)I(\theta \in A)$$</p>
<p>where $A$ is a subset of the parameter space and $I(r)$ is 1 if $r$ is true and 0 otherwise -- is also a conjugate prior.</p>
<p>Basically, if we ... | 72,659 |
<p>I am doing CFA to test for common method bias using an unmeasured latent construct method. The average common variance I am getting from the common factor is about 31% which is high (as should be less than 25%).</p>
<p>I checked for differences in p-values of the trait loadings (between CFA model with ULC and witho... | 72,660 |
<p>I am generating models and each model is a random sample of the total model population. It is recommended that I generate 30,000 models and cluster taking the top 5 to 10 clusters to reach the native state.</p>
<p>I would like to adjust the 30,000 number lower but still remain within the probable range of the nativ... | 72,661 |
<p>I have a set of 10 items each with a weight between 0-1. A person can rate each of these 10 items with a score between 0-100, but is given, say, only 500 points to allocate among these 10 items The person does not know the weight of each item and the total score will be the weighted average.</p>
<p>A person could... | 45,859 |
<p>I have a data set where a person has no disability, a mild disability, or a severe disability. I want to determine of the model for mild and severe disabilities are the same.</p>
<p>I estimated three logits using the same set of independent variables (X's)</p>
<p>In the first model the dependent variable Y1 = 1 i... | 72,662 |
<p>Suppose I want to know whether a baseball team's winning percentage the previous season or the <a href="http://en.wikipedia.org/wiki/Pythagorean_expectation" rel="nofollow">Pythagorean expectation</a> of that team from the previous season is a better predictor of next season's win percentage. (I take percentages bec... | 72,663 |
<p>I have a couple of questions for prediction and tolerance intervals.</p>
<p>Let's agree on the definition of the tolerance intervals first: We are given a confidence level, say 90%, the percentage of the population to capture, say 99%, and a sample size, say 20. The probability distribution is known, say normal for... | 30,888 |
<p>We have an application where we're trying to quantify the total risk(hitting traffic, say) of a trip in a car where probability is a function of time and a series of algorithms:</p>
<p><img src="http://i.stack.imgur.com/nMP78.png" alt="Our probability graph with error bars"></p>
<p>How can we quantify the 'total' ... | 72,664 |
<p>This is a basic question. I have been handed a binary logistic regression. The model has significant terms, but the goodness of fit tests indicates the logit model is not appropriate. The author of the study indicates that the goodness of fit data does not invalidate the relationship between the dependent variabl... | 72,665 |
<p>I have two questions on using random forest (specifically randomForest in R) for missing value imputation (in the predictor space). </p>
<p>1) How does the imputation algorithm work - specifically how and why is the class label required for imputation? is the proximity matrix which serves to weight the average valu... | 45,871 |
<p>I have a panel data set (country and year) on which I would like to run a cluster analysis by country. My data set has around 20 variables. </p>
<p>Here's a summary for my panel data:</p>
<p><code>panel variable: country (strongly balanced)
time variable: year, 2010 to 2013</code></p>
<p>Running a kmeans clust... | 72,666 |
<p>How would I go about computing the sample size for repeated measures ANOVA design, given power, significance and the required effect size (2 groups, I know the mean difference that I want to be able to catch and approximate standard deviation)?</p> | 72,667 |
<p>This is a follow up question to <a href="http://stats.stackexchange.com/questions/87921/how-do-i-test-if-two-non-normal-distributions-differ/87936?noredirect=1#87936">"How do I test if two non-normal distributions differ?</a></p>
<p>I have 13 distributions, <img src="http://i.stack.imgur.com/eLKCE.png" alt="X vs Y"... | 72,668 |
<p>I am doing master in statistics and I am adviced to learn differential geometry. I would be happier to hear about statistical applications for differential geometry since this would make me motivated. Does anyone happen to know applications for differential geometry in statistics, please? Thank you!</p> | 12,588 |
<p>I am running a project which compares citation counts across datasets per year, and then wants to plot the general change in the frequency in which a given source is cited. Here are two example datasets:</p>
<p>1999 - SOURCE A</p>
<pre><code>{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 23, 70, 0, 0, 0, 0, 0, 0, 0, 32, 0,
0,... | 72,669 |
<p>The graph below shows GPS heading data (sampled every second) and I am trying to find the best way to detect (right/left) turns in the data. Appreciate suggestions for algorithms/methods for it (perhaps step detection)? </p>
<p><img src="http://i.stack.imgur.com/nFMPt.png" alt="GPS heading sampled 1 sec apart"></p... | 72,670 |
<p>I'm trying to recreate the MNL analysis like this <a href="https://ub-madoc.bib.uni-mannheim.de/1647/1/working_paper_6_2007.pdf" rel="nofollow">paper</a> or this <a href="https://ub-madoc.bib.uni-mannheim.de/1647/1/working_paper_6_2007.pdf" rel="nofollow">one</a>.</p>
<p>In Excel I have a sheet with my choice colum... | 72,671 |
<p>I examined the influence of ADHD on abnormal bodyweight in a very large, national sample of children. In my multinomial regressions, I controlled for several specific confounds, which have been shown to be associated with both ADHD and bodyweight in previous studies. One of these confounds was ADHD medication. Altho... | 72,672 |
<p>In a recent lecture I was told that, in order for the maximum likelihood estimate to be valid, the log likelihood needs to go to minus infinity as the parameter goes to the boundary of the parameter space. But I don't understand why this is essential. Suppose the log likelihood goes to some kind of asymptote. Then t... | 72,673 |
<p>I have found Cointegration based on Engle/ Granger and Johansen. However, Granger-causality is rejected for both variables. How is that possible?</p>
<p>According to theory,
if x and y are I(1) and cointegrated, x is Granger causal to y and/or y is Granger causal to x.
However, Granger-causality has been rejected... | 34,664 |
<p>Is there any unique property of $\mathrm{Gamma}(k=e, \text{ scale})$ or a Negative binomial distribution with $r=e$? Here, $e$ is Euler's number, $e \approx 2.71828$.</p>
<p>The reason I'm asking is that one of the variables in my computer simulations can be fitted by $\mathrm{Gamma}(k=e, \text{ scale})$ or by $\ma... | 72,674 |
<p>Do Bayesians ever argue that their approach generalizes the frequentist approach, because one can use non-informative priors and therefore, can recover a typical frequentist model structure?</p>
<p>Can anyone refer me to a place where I can read about this argument, if it is indeed used?</p>
<p>EDIT: This question... | 72,675 |
<p>I've plotted the learning curves below, using different RF trainers. The training set is very small and with few features (it's the popular <em>Titanic</em> dataset). At pre-processing stage, I just created a set of dummy vars from my original factor features. I then used the AUROC to choose the best value for mtry.... | 7,439 |
<p>I have the list of time series. I am fitting these series with the formula $$y=ax^2\exp(b*x)$$. It should be noted that parameter $b$ in the formula must be negative as this reflects the behaviour of time series. An example plot for the fitted regression output using <code>nls()</code> in R is:
<img src="http://i.st... | 72,676 |
<p>To build two linear regression model, (dependant var : B, independant vars : A1, A2, A3) I have to set the cut point of A1. (high A1 and low A2) I want to pick up the model*s*(a model for high A1, and the other for low A2) with with the lowest residual sums of square*s*</p>
<p>In summary, How I can get the optimal ... | 34,666 |
<p>A famous car production company produces 3 different models of cars, available in 5 colors and 3 possible CC(1900 cc,2000 cc and 2200 cc). suppose that every combination of model, color and CC has equal probability to be selected by a client:</p>
<ul>
<li>If in one week 6 cars are sold, what is the probability that... | 34,667 |
<p>I have a dataset of approx 1000 members and 100 variables
modelling is multivariable using mainly partition methods and also some neural net experimentation</p>
<p>I have been experimenting with 3 way validation using both 60-20-20 and 70-15-15</p>
<p>the problem i have is this: Using 3 way validation and running ... | 34,668 |
<p>I'm looking at multiple live data streams which I process on a daily basis and would like to monitor in real time. </p>
<p>The way I did it at first was to introduce a somewhat arbitrary upper bound for each of the streams..the monitoring would look at time elapsed between consecutive stream items and if it exceeds... | 72,677 |
<p>Suppose $X1,..,X4$ be iid from pdf $f(x|\theta)=\frac{1}{\theta}$ ,for $0<x<\theta$. </p>
<p>The prior distribution is </p>
<p>$\pi(\theta)=\frac{2}{\theta^3}$ , for $\theta>1$</p>
<p>I have to obtain:</p>
<p>a)posterior distribution of $\theta$ given $Y$, where $Y = max(X1,...,X4)$. </p>
<p>b)point e... | 72,678 |
<p>The R documentation for either does not shed much light. All that I can get from <a href="https://stat.ethz.ch/pipermail/r-help/2007-December/147855.html">this link</a> is that using either one should be fine. What I do not get is why they are not equal.</p>
<p>Fact: The stepwise regression function in R, <code>ste... | 34,670 |
<p>I've performed a random search in hypothesis space $$\{(c,h)| c \in U[1,256]; h\in U[1,100];c \in \mathrm{Z} \text{ and } h \in \mathrm{Z}\}$$ that defines the parameters of a standard multilayer perceptron (MLP) neural network. </p>
<p>In each step of the random search, I draw two parameters $c$ and $h$. $c$ defi... | 34,671 |
<p>I have a semi-small matrix of <strong>binary features</strong> of dimension 250k x 100. Each row is a user and the columns are binary "tags" of some user behavior e.g. "likes_cats".</p>
<pre><code>user 1 2 3 4 5 ...
-------------------------
A 1 0 1 0 1
B 0 1 0 1 0
C 1 0 0 ... | 72,679 |
<p>I have two populations, One with N (no of observations)=38704 and other with N=1313662. These data sets have some 25 variables, all continuous. I took mean of each in each data set and computed the test statistic using the formula
(t=mean difference/std error). The problem is of the degree of freedom. By formula of... | 45,908 |
<p>I have some objective and subjective variables. My aim is to create a statistical index which defines variables and interrelations of variables accurately.</p>
<p>For instance, suppose that I am creating a spirituality index including demographic variables and also subjective variables like religious perceptions et... | 72,680 |
<p>What is the formula of P(W) at this Bayesian network?</p>
<p><img src="http://i.stack.imgur.com/sZilQ.png" alt="enter image description here"></p>
<p><strong>PS 1:</strong> Is that formula gives me P(W) or not:</p>
<p>P(Cloudy) × P(Sprinkler|Cloudy) × P(Rain|Cloudy) × P(Wet Grass | Sprinkler, Rain)</p>
<p><stron... | 40,330 |
<p>We are monitoring Air Quality: essentially concentrations. We collect time series and we periodically calibrate analysers in order to control the process. Knowing the specifications or assessing it experimentally we have, for each analyser, some low threshold on the dynamic range (measurement extent) where data beco... | 34,673 |
<p>I would like to estimate a standard logit (panel data):</p>
<p>$\text{logit}(P(y_{i,t}=1))= \alpha + \beta_1 x^1_{i,t} + \beta_2 x^2_{i,t} +\epsilon_{i,t}$. </p>
<p>The problem I am facing, however, is that $x^2$ is <em>yearly</em>, whereas $y$ and $x^1$ are <em>monthly</em>. Aggregating $x^1$ to the yearly level ... | 72,681 |
<p>I'd like to make an assertion about whether individuals in my dataset exceed legal standards for commitment, which is largely determined by estimated risk of recidivism. I have estimated a logit model predicting recidivism. Here is sample code written trying to determine what percentage of individuals had predicte... | 72,682 |
<p>What are some of the applications of a HMM in the marketing field - specifically CRM and targeted marketing?</p>
<p>For example, is it mainly for predicting an outcome given a sequence? Such as if web site visitor visits {Page 2, Page 54, page 23} what is the probability they will $<next>$ visit page 22? Or v... | 72,683 |
<p>This is probably a stupid question, but here goes: so we want to approximate the following expectation:
$$\mathbb{E}[h(x)] = \int h(x)\pi(x) dx$$
Where $h(x)$ is an arbitrary function and $\pi(x)$ is a distribution, also for simplicity, let's assume that we actually know the normalizing constant for $\pi(x)$. Of c... | 72,684 |
<p>I have data on a number of studies comparing response rates to various treatments of a disorder. There are six different treatments, and some studies only test a single treatment. For each treatment in each study, I have the response rate and the sample size (plus some other variables). </p>
<p>Normally, if there w... | 38,192 |
<p>Question from a stats novice and StackExchange newb, an anthropologist with a computer science background. I'm looking for an appropriate statistical measure for 'synchrony' as in the following situation:</p>
<p>I have a panoramic video of several people sitting in chairs around the camera having a conversation for... | 34,679 |
<p>I'm trying to use the Match() function from the Matching package in R to do a propensity score analysis.</p>
<p>My outcome of interest is a binary variable (0/1). My treatment is also a binary variable (0/1). In addition, I have a number of other variables that I want to control for in this analysis.</p>
<p>Firs... | 72,685 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.