question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I am trying to compare two (univariate) data sets using the <code>HellingerDist</code> function described <a href="http://www.inside-r.org/packages/cran/distrEx/docs/HellingerDist" rel="nofollow">here</a>. However, this package only allows the a <code>numeric</code> type with one of the distribution classes. Is it p... | g64922 | [
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<p>This is similar to the question <a href="http://stats.stackexchange.com/questions/4044/measuring-the-distance-between-two-multivariate-distributions">Measuring the "distance" between two multivariate distributions</a>, except that I want to measure distance between two data sets. I can imagine simply comp... | g23288 | [
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... |
<p>According to <a href="https://www.google.ie/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&ved=0CDoQFjAC&url=http://www.stanford.edu/~hastie/Papers/spc_jcgs.pdf&ei=gaWdUpTLDKHH7AaRkIGoBg&usg=AFQjCNH5mw9Fbq3eAwDtpsJNtMLr_BedCw&bvm=bv.57155469,d.ZGU" rel="nofollow">this pa... | g64923 | [
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<p>I am testing two path analysis models. Both models have the same predictors. The outcome variable is all that differs</p>
<ul>
<li>Model 1: Outcome variable is intention to use a face-to-face support service</li>
<li>Model 2: Outcome variable is Intention to use a telephone support service</li>
</ul>
<p>When I tes... | g64924 | [
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<p>I took two statistics classes at college and I remember "hypothesis testing" to be a very powerful tool if only I could apply it correctly. It seems that while I was in college solving problems, I was always given the population's standard deviation to solve the question. However, what if I want to apply it in my jo... | g64925 | [
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<p>What is the best way or steps to calculate the moment generating function (mgf) of (1+sum of gamma distribution) over gamma distributions? Is it the same way to derive beta distributions?</p>
<p>I am trying to find the mgf of $$\exp[-(1+\sum X_j)/Y]$$</p>
<p>where $X$ are gamma distributions that have the same sca... | g64926 | [
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<p>I have some confusion about the kind of sampling I'm using. I started by choosing the manufacturing sector and within it, chose 4 industries. Later I distributed questionnaires within those 4 industries as per my convenience (convenience sampling). </p>
<p>What kind of sampling am I using?</p> | g23291 | [
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<p>For $i=1, \ldots, K$ and $j=1, \ldots,n$, assume the following model.
\begin{align}
X_{ij} \mid \mu_i, \sigma^2 & \stackrel{_\text{ind}}{\sim} N(\mu_i, \sigma_i^2) \\
\mu_i & \stackrel{_\text{iid}}{\sim} N(\mu, \tau^2) \\
\ln(\sigma_i^2) & \stackrel{_\text{iid}}{\sim} N(\mu_v, \tau_v^2)
\end{align}
Is it... | g64927 | [
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<p>In document classification (document categorization) field, researchers recommend always a few standard dataset, such as Reuters-21578, RCV1(Reuters Corpus Volume 1). However, these datasets only contain documents related to specific domain, for instance, <strong>newswire stories</strong>. </p>
<p>However, if we re... | g64928 | [
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<p>I am working on a Capacity Planning assignment and I have read some books. This is specifically about distributions. I use R.</p>
<ol>
<li><p>What is the recommended approach to identify what my data distribution is ? I have this diagram but are there statistical methods to identify it ?</p>
<p><img src="http://i.... | g37809 | [
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<p>I need to calculate the cumulative distribution function of a data sample. </p>
<p><strong>Is there something similar to hist() in R that measure the cumulative density function?</strong></p>
<p>I have tries ecdf() but i can't understand the logic.</p> | g64929 | [
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<p>38% claim to have at least one tattoo. If you asked 15 people, what is the probability that none of them have a tattoo? What is the probability that at least 10 of them have a tattoo?</p> | g64930 | [
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<p>The PDF of the ratios of independent beta variables is described in <a href="http://www.tandfonline.com/doi/abs/10.1080/03610920008832632#.U9J02vldUcC" rel="nofollow">http://www.tandfonline.com/doi/abs/10.1080/03610920008832632#.U9J02vldUcC</a></p>
<p>To explore the implications, i created an implementation in pyth... | g64931 | [
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<p>Background: I have conducted some testing on a random sample of n=20 parts. The data is variable and I know nothing about the population statistics. I would like to use the data from this sample to make statements about the population (in particular, I would like to say with 95% confidence that the 99th percentile... | g64932 | [
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<p>Gaussian data distributed in a single dimension requires two parameters to characterise it (mean, variance), and rumour has it that around 30 randomly-selected samples is usually sufficient to estimate these parameters with reasonably high confidence. But what happens as the number of dimensions increases?</p>
<p>I... | g64933 | [
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<p>I wish to test the following Hypothesis:</p>
<p>H = "sales growth from previous year" predicts "sales growth this year"</p>
<p>I have the following data:</p>
<pre><code>> head(x)
Location Week Sales_Y1 Sales_Y2 Sales_Y3 Y2_vs_Y1 Y3_vs_Y2
1 1_1 5 24924.50 21665.76 23510.49 0.8692556 1.0851449
2 ... | g64934 | [
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<p>In the following blog post: <a href="http://blog.thinknewfound.com/oscillatory-similarity/" rel="nofollow">here</a>, the author goes and calculates the alternative correlation measure for two time series. Essentially, calculates the correlation between two series by giving the mean of each series 0. I tried reprodu... | g64935 | [
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<p>The title is a bit complex, so I'll just post the question. This is in preparation for a final I'm going to take.</p>
<blockquote>
<p>Consider the total number of cars that a car dealership might sell over $50$ randomly selected (contiguous) days. Assume that the expected value of the number of cars sold over suc... | g64936 | [
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<p>I'm tuning a slot machine app and need to make sure the mini-game is appropriately balanced.</p>
<p>The mini-game is a grid of 30 treasure chests, 6 of which are traps. The user continues to open chests (and earn prizes) until they hit a trap.</p>
<p>What I'd like to do is add a "lives" mechanic where hitting a t... | g43086 | [
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<p>Un-informative priors are preferred in instances where bias is not acceptable (ie. courtrooms, etc.)</p>
<p>However, it seems to me that it would just make sense to use a frequentist approach instead. Why does the Bayesian approach even have a non-informative prior?</p>
<p>Thanks!</p> | g64937 | [
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<p>Background:
- I have a country with 8 states
- Each state has different population size, some much larger than others
- I've recorded the number of campaign respondents from each state</p>
<p>Problem:
- I'd like to compare the respondents between each state
- But one might argue that the larger states will always ... | g23297 | [
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<p>Why there is difference between lowess smoother plot and regression plot in the following plot?</p>
<p><img src="http://i.stack.imgur.com/z5g3A.jpg" alt="enter image description here"></p>
<p>I run packages: "datasets" "utils" "graphics" "stats" "methods" in RStudio.</p> | g64938 | [
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<p>I have several intermittent data. Based on those data, I would like to compare several forecasting methods (Exponential Smoothing, Moving Average, Croston, and Syntetos-Boylan), and decide whether Croston or Syntetos Boylan is better than SES or MA for intermittent data or not. The measure I'd like to compare is Mea... | g64939 | [
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<p>In a $2^5$ design, it is believed that only the main effects $(A,B,C,D, E)$ and $AB,AC$ interaction effects are non-zero. I need to construct a fractional factorial with minimum number of runs which can be used to estimate all the main effects and $AB,AC$ interaction effects .</p>
<ul>
<li><p>i hoped this be a $2^{... | g64940 | [
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<p>If you have the following histogram, how do you calculate the mean if you do not know the upper limit of the final interval:</p>
<pre><code>Range Freq.
20-30 5
30-40 2
40+ 4
</code></pre> | g64941 | [
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<p>I'm looking for paper(s) that talk about "why low $R^2$ value is acceptable in social science or education research". Please point me to the right journal if you know one. </p> | g23299 | [
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<p>I would like to multiply x with two different values based on the mod function.</p>
<pre><code>if (x mod 2=0)
then x=x*2.15
else if (x mod 2>0)
then x=x*3.15
</code></pre>
<p>My sample is</p>
<pre><code>x <- sample((10:30),size=15,replace=T)
</code></pre>
<p>I need do this in R programming function.</p> | g64942 | [
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<p>If $X_i$, $i =1,...,n$ all follow a normal distribution $N(\mu,\sigma^2)$, and are independent,
does $\frac{\sqrt{n}\cdot(\frac{1}{n}\cdot \sum X_i - \mu)}{\sqrt{(\frac{1}{n}\cdot \sum (X_i-\mu)^2)}}$ follow a student t-distribution with n degrees of freedom?
I am aware of the classic formula with the n-1 degrees of... | g64943 | [
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<p>I work for a manufacturing company that collects times (man-hours) for tasks. The tasks are similar in concept from one product to another, but the characteristics of the product can vary (like size, voltage, etc).</p>
<p>It has been something like ten years since I've had to do any heavy lifting in terms of data ... | g23303 | [
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<p>I am trying to compare Cox model with ANN by R but I have some problems.</p>
<ol>
<li><p>the result of package <code>coxph</code> is hazard but the result of package <code>nnt</code> is survival time</p></li>
<li><p>How to create labels in ROC curve in <code>rocr</code> package.</p></li>
<li><p>How to calculate c... | g64944 | [
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0.07872076332569122,
-0... |
<p>I am trying to fit a bivariate cluster model with X and Y. What I would like to do is discard (make not clustered / un-grouped) that are far from the cluster center (for example $\mu$ + 2*standard deviation) at each direction. </p>
<pre><code>X2 <- c(rnorm(150, 10, 1),rnorm(50, 10, 5), rnorm(150, 25,1),
rn... | g126 | [
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0.00720624066889286,
0.01740829087793827,
0.04342774301767349,
0.04371364414691925,
-0.037601... |
<p>As a beginner to MDS, here is my thought process:</p>
<p>Given a data set of environmental factors that may effect a certain sites, when I run a PCA on each site I get a list of principal components. If I want to understand which environmental factors are driving each of the principal components, ie:</p>
<pre><cod... | g64945 | [
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0.0013727296609431505,
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0.0743371918797493,
0.023642290383577347,
0.05893987789750099,
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<p>For a distribution $X$, assuming it's "normalized" so that $E\{X\}=0$ and $Var\{X\}=1$.</p>
<p>Given significance level $\alpha$, define "Fat Tail Ratio" as
$$FTR(X,\alpha) = z_{1-\alpha/2} - z_{\alpha/2} $$</p>
<p>where $z_{\alpha/2}$ and $z_{1-\alpha/2}$ means
$P\{x<z_{\alpha/2}\} = \alpha/2$, and $P\{x<z... | g64946 | [
0.04632110148668289,
0.026900917291641235,
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0.0228899996727705,
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0.012351727113127708,
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0.01592053286731243,
-0.03156261146068573,
0.0019468835089355707,
-0.018662750720977783,
0.03233828768134117,
0.0305... |
<p>Grants often require power analysis to support a proposed population size. In proteomics (and most -omics), there are 100's to 1000's of features/variables measured across 10's of samples (maybe 100s, but unlikely). Also, it is known that some of these measurement units (e.g., spectral counts of proteins) are not no... | g64947 | [
-0.018490811809897423,
0.00019759696442633867,
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0.022300731390714645,
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0.007940003648400307,
0.06425537168979645,
0.017544593662023544,
0.007067551836371422,
0... |
<p>I am trying to fit a Gumbel distribution to a set of N i.i.d. data points. I was wondering whether there is a conjugate prior to infer the two parameters of the Gumbel pdf.</p> | g46379 | [
0.06282484531402588,
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0.001188205904327333,
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0.... |
<p>I used a -4 to +4 Likert scale in one set of questionnaires and -3 to +3 for the same questionnaires, but gathered respondents in a different way. I want to rescale from -4 to +4 down to -3 to +3 for the second group. </p>
<p>How do I do this and secondly is there a referenced/accepted procedure for doing this?</p> | g64948 | [
0.00036196241853758693,
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0.02079704962670803,
0.02076234295964241,
0.011280911043286324,
0.047155532985925674,
0.0179... |
<p>Sites like eMarketer offer general survey results about internet usage.</p>
<p>Who else has a big set of survey results, or regularly releases them?</p>
<ul>
<li>Preferably marketing research focused.</li>
</ul>
<p>Thanks!</p> | g64949 | [
-0.05362437292933464,
0.011569039896130562,
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0.01580648124217987,
0.07798606157302856,
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... |
<p>Does mutual information discriminate against fold change differences?</p> | g23311 | [
0.012385774403810501,
0.001408289186656475,
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0.006641964428126812,
... |
<p>My father is a math enthusiast, but not interested in statistics much. It would be neat to <em>try</em> to illustrate some of the wonderful bits of statistics, and the CLT is a prime candidate. How would you convey the mathematical beauty and impact of the central limit theorem to a non-statistician? </p> | g64950 | [
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0.... |
<p>I've been asked to give some advice for some clinicians who are comparing two different methods of blood pressure measurement. I suggested to them that we should proceed with a two-one-sided-test technique to determine equivalence of the two techniques.</p>
<p>Unfortunately I have now learned that the clinicians h... | g23312 | [
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0.004780378192663193,
0.038052480667829514,
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... |
<p>Having just recently started teaching myself Machine Learning and Data Analysis I'm finding myself hitting a brick wall on the need for creating and querying large sets of data. I would like to take data I've been aggregating in my professional and personal life and analyze it but I'm uncertain of the best way to do... | g64951 | [
0.002963362028822303,
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0.044291213154792786,
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0.0831417366862297,
0.03... |
<p>I am working on some MRSA data and need to calculate the relative risk of a group of hospitals compared with the remaining hospital.</p>
<p>My colleagues throws me an excel with a formula inside to calculate the "exact confidence interval of relative risk", I can do the calculation without difficulties, but I have ... | g64952 | [
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0.000003013292825926328,
0.063135527074337,
0.08413268625736237,
-0.043... |
<p>a) For a given significance-level $\alpha$, if we find $\mathop{\mathbb E}(b-a)$ such that $\mathbb P(a \leq X \leq b) \geq 1−\alpha$ for all possible values of $a$ and $b$, from the point of view of interpretability, what extra interpretability does the expected length buy us?</p>
<p>Say, if I had observed proport... | g64953 | [
0.015948530286550522,
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0.00542048504576087,
0.009514776058495045,
0.006216317415237427,
0.015998151153326035,
-0.0087... |
<p>I have a variable NPS which is an item on a survey, the answer format is ordinal, 0 to 10.</p>
<p>Then there are sub-questions on the same survey, some are ordinal, some are categorical.</p>
<p>I would like to determine which sub-question or which group of sub-questions are the best predictors of NPS. The goal is ... | g64954 | [
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0.0017240437446162105,
0.0699993148446083,
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0.025514302775263786,
0.027... |
<p>Let us say I have a bunch of rows for a classification problem:</p>
<p>$$X_1, ... X_N, Y$$</p>
<p>Where $X_1, ..., X_N$ are the features/predictors and $Y$ is the class the row’s feature combination belongs to. </p>
<p>Many feature combination and their classes are repeated in the dataset, which I am using to fit... | g64955 | [
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0.029883431270718575,
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0.06432320177555084,
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0.040965717285871506,
0.022627150639891624,
0.0599471852183342,
-0.025357648730278015,
... |
<p>I've been reading a lot lately about the differences between Fisher's method of hypothesis testing and the Neyman-Pearson school of thought.</p>
<p>My question is, ignoring philosophical objections for a moment; when should we use the Fisher-approach of statistical modelling and when should be use the Neyman-Pearso... | g64956 | [
0.03067976050078869,
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0.014111639000475407,
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0.037019506096839905,
0.049828555434942245,
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0.030443158000707626,
0.07443559169769287,
-0.021027417853474617,
0.06162107735872269,
0.0... |
<p>For fun, I tried to replicate the results of <a href="http://rpproxy.iii.com:9797/MuseSessionID=248c435aa056d82d70d390e949c628fb/MuseHost=rfs.oxfordjournals.org/MusePath/content/22/1/435.abstract" rel="nofollow">Petersen (2009)</a> who deals with the correct estimation of standard errors in finance panel data sets. ... | g64957 | [
0.008916943334043026,
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-0.021633844822645187,
-0.02618461102247238,
0.030780570581555367,
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0.04298064857721329,
0.014894608408212662,
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-0.006264094728976488,
0.0038956664502620697,
0.07534550130367279,
0.035623110830783844,
-0.0... |
<p>The Kolmogorov–Smirnov distribution is known from the <a href="http://en.wikipedia.org/wiki/Kolmogorov_Smirnov" rel="nofollow">Kolmogorov–Smirnov test</a>. However, it is also the distribution of the supremum of the Brownian bridge.</p>
<p>Since this is far from obvious (to me), I would like to ask you for an intui... | g64958 | [
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0.01544428151100874,
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0.037246234714984894,
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0.07842819392681122,
0.07349244505167007,
-0.02445453219115734,
-0.01693931594491005,
0.005165173672139645,
-0.0048635597340762615,
0.019... |
<p>Suppose one has a relatively large number of observations, each of which consists of a continuous result and a small number (2 or perhaps 3) of categorical variables, each of which has a large cardinality (up to 10k or so). So, for instance, one might wish to predict income given a person's university and chosen in... | g29023 | [
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0.0019154073670506477,
-0.027690593153238297,
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0.018997546285390854,
0.044086750596761703,
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0.014228296466171741,
-0.035565607249736786,
0.015310774557292461,
0.05804058164358139,
0.... |
<p>I know that the pdf of a power law distribution is $$ p(x) = \frac{\alpha-1}{x_{\text{min}}} \left(\frac{x}{x_{\text{min}}} \right)^{-\alpha}$$</p>
<p>But what does it intuitively mean if, for example, stock prices follow a power law distribution? Does this mean that losses can be very high but infrequent? </p> | g23319 | [
0.02695699967443943,
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0.031983520835638046,
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0.02616012655198574,
... |
<p>I am looking for some medium to long length papers/websites/etc about data mining, specifically where one dataset is explored in depth from data preparation through final model. I am particularly interested in discussions about application of machine learning algos and also basic data modeling. An example would be... | g64959 | [
0.019391493871808052,
0.023767463862895966,
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0.04019166901707649,
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-0.012806776911020279,
0.03529537841677666,
0.00951264426112175,
0.09551046043634415,
-0.02... |
<p>I am writing a hierarchical BUGS model that involves both linear and angle variables. I want the hyper-parameters to be normally distributed, which is straight-forward for the linear variables, but I'm not sure what to do about the angle variables. I would gladly use a von Mises distribution or a truncated normal, b... | g23321 | [
0.05360197648406029,
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-0.010059770196676254,
-0.008630677126348019,
0.017314380034804344,
-0.024576455354690552,
0.0... |
<p>I am working with a data set having N around 200,000. In regressions, I am seeing very small significance values << 0.001 associated with very small effect sizes, e.g. r=0.028. What I'd like to know is, is there a principled way of deciding an appropriate significance threshold in relation to the sample size?... | g64960 | [
-0.008257145993411541,
0.06960350275039673,
0.004387666936963797,
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0.030504178255796432,
0.053938090801239014,
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-0.04053217172622681,
0.035191360861063004,
-0.0025988039560616016,
0.035415612161159515,
... |
<p>I need to know the formula for the pdf of $S^2$.</p>
<p>I know this:</p>
<p>$$
\frac{(n-1)S^2}{\sigma^2} \sim \chi^2_{n-1} \>,
$$</p>
<p>but I want to state the correct formula for the pdf of $S^2$, not $(n-1)S^2/\sigma^2$.</p>
<p>Any thoughts?</p> | g23322 | [
-0.0069060130044817924,
0.0018278813222423196,
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0.01455067191272974,
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0.025451835244894028,
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0.058168962597846985,
-0.023117201402783394,
0.038220398128032684,
0.013728372752666473,
... |
<p>I was reading a Wikipedia article on <a href="http://en.wikipedia.org/wiki/Birthday_problem" rel="nofollow">the birthday paradox</a> and stumbled upon the following statement:</p>
<blockquote>
<p>...the pairings in a group of 23 people are not statistically equivalent to 253 pairs chosen independently...</p>
</bl... | g16790 | [
-0.03327752649784088,
0.1016162559390068,
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0.006095206364989281,
0.011763383634388447,
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0.02749146707355976,
0.055151067674160004,
0.03718078136444092,
-0.006614255253225565,
-0.030929507687687874,
0.023195328190922737,
-0.0016958413179963827,
0.... |
<p>Are there examples of learning algorithms(other than k-means clustering) which fit the paradigm of Hard-EM?</p>
<p>By hard EM, I mean the variant described in <a href="http://ttic.uchicago.edu/~dmcallester/ttic101-07/lectures/em/em.pdf" rel="nofollow">here</a>.</p> | g64961 | [
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0.03380722552537918,
0.034432750195264816,
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0.11626332253217697,
-0.001... |
<p>I have some measurement data of estimates vs actuals (of some metric $m$). For every such data I also have the ratio of $\frac{actuals}{estimates} = r \space (say)$ - if this ratio is greater than 1 it implies underestimation (and overestimation if less than one).</p>
<p>Given I have substantial data, about 100 or ... | g29025 | [
0.0018247266998514533,
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-0.03444117307662964,
0.024470211938023567,
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0.04586418718099594,
0.02499680034816265,
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-0.053183212876319885,
0.022169316187500954,
0.020927486941218376,
0.05969873443245888,
-0... |
<p>I found this:
<img src="http://i.stack.imgur.com/WTaPr.png" alt="enter image description here">
<a href="http://www2.cs.uregina.ca/~dbd/cs831/notes/confusion_matrix/confusion_matrix.html" rel="nofollow">http://www2.cs.uregina.ca/~dbd/cs831/notes/confusion_matrix/confusion_matrix.html</a></p>
<p>defining TP,FP,TN, F... | g708 | [
0.027741828933358192,
0.017172200605273247,
-0.018933730199933052,
-0.023388905450701714,
0.0815250426530838,
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0.05863348767161369,
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-0.03919917717576027,
-0.011259971186518669,
0.052289098501205444,
-0.008276480250060558,
0.05336457118391991,
-0.0... |
<p>I have a time series prediction problem where the aim is to forecast the average value of $y_t$ over the next $T$ periods, given all the information available up to point $t$. For example, I want to forecast</p>
<p>$$\bar{y}_t = \frac{1}{T}\sum_{k=1}^T y_{t+k}$$</p>
<p>as a function of a bunch of other variables $... | g64962 | [
-0.0073943897150456905,
0.041508883237838745,
0.03426231071352959,
0.005048012360930443,
-0.021092981100082397,
0.008442708291113377,
0.043076977133750916,
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0.01563069596886635,
0.070119209587574,
-0.004637530539184809,
0.022213608026504517,
-0.0... |
<p>This may for sure be a stupid question but suppose a model </p>
<p>\begin{equation}
y = \alpha \times r^\gamma \times \varepsilon
\end{equation}</p>
<p>the parameters $\alpha$ and $\gamma$ are of interst for me (and $\varepsilon$ is the standard error term). so my first intention was do take the $log()$ of the f... | g48241 | [
0.004446255974471569,
-0.05037914589047432,
-0.008222324773669243,
0.005904262885451317,
0.04455452784895897,
0.018517810851335526,
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0.0043317778035998344,
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0.004116719122976065,
-0.03577055782079697,
0.021710021421313286,
0.009787183254957199,
-0.... |
<p>I am doing some research comparing low frequency oscillations in heart rate with palpated/observed phenomena. I am using a heart rate monitor to collect data and simultaneously asking an observer/palpator to note the occurrence of (possibly related?) phenomena and recording the timings of these events.</p>
<p>The f... | g64963 | [
0.023427393287420273,
-0.023368794471025467,
-0.025683581829071045,
-0.006186087615787983,
0.053641337901353836,
-0.0131338220089674,
0.06313861161470413,
-0.004618667997419834,
0.01097284909337759,
-0.09039084613323212,
0.008170010522007942,
0.034338537603616714,
0.04278644546866417,
0.02... |
<p>After applying quantile regression with t=0.5,0.6 on the data set WBC(
Wisconsin Breast Cancer)with 678 observations and 9 independent
variables($inp_1,inp_2,...inp_9$) and 1 dependent variable(op) I have got the
following results for beta values.</p>
<pre><code>| t | 0.5 | 0.6 |
| b1 ... | g43143 | [
-0.006517908535897732,
-0.06774889677762985,
-0.021129198372364044,
-0.026896655559539795,
0.06572791188955307,
-0.02031003311276436,
0.1013682410120964,
-0.024446940049529076,
-0.05701414495706558,
-0.04245087504386902,
-0.06946996599435806,
0.04908442869782448,
0.012713396921753883,
0.01... |
<p>Imagine I have a network, and in this network I have n nodes of interest.</p>
<p>I calculated the average shortest path between these nodes.</p>
<p>I want to see if they are statistically significantly close to each other.</p>
<p>Therefore I select n nodes from the network randomly, and work out the average short... | g64964 | [
0.019569657742977142,
-0.0010068294359371066,
-0.021267855539917946,
-0.02658935822546482,
0.036086034029722214,
-0.049432288855314255,
0.017667127773165703,
0.013283055275678635,
-0.014737927354872227,
0.020216375589370728,
0.0075783501379191875,
0.01734226755797863,
0.0387466624379158,
0... |
<p>I would like to find the answer to the following question. A casino offers games with one of the following 21 p’s [0; 0.05; 0.10 .... 0.90; 0.95; 1] and one of the following 21 v’s (values) [0; 5; 10 ... 90, 95, 100]. The person taking part in the game either wins the v or he gets nothing.</p>
<p>In sequence A, 98... | g64965 | [
-0.012866909615695477,
0.014584013260900974,
-0.009873650968074799,
-0.005766098853200674,
-0.018698856234550476,
-0.006932105403393507,
0.01984354481101036,
-0.01344379223883152,
-0.03764345124363899,
0.0039044928271323442,
-0.0721992552280426,
0.01979888044297695,
-0.01378775667399168,
-... |
<p>My research is a about clustering a huge data set. Right now I'm not using any technique for feature selection, because I only need 3 attributes from each row. I hope I'm making myself clear, lets say I have 1000 rows of data and in each row there are at least 15 attributes (field with different category, e.g. IP ad... | g64966 | [
0.008762932382524014,
0.003094063140451908,
0.026442160829901695,
-0.02276722714304924,
0.014605817385017872,
-0.047839630395174026,
0.05498713627457619,
0.022310961037874222,
-0.05192293971776962,
-0.02351623959839344,
0.052322130650281906,
0.008725760504603386,
0.041716594249010086,
-0.0... |
<p>Can a unimodal multivariate distribution have a multimodal marginal distribution? </p>
<p>If all marginal distributions are unimodal, can the multivariate distribution be multimodal?</p> | g23332 | [
0.029463229700922966,
-0.01047660131007433,
0.010170075111091137,
-0.039816685020923615,
-0.00721445307135582,
-0.006507894489914179,
-0.04789202660322189,
-0.010550791397690773,
0.014043913222849369,
0.02655731700360775,
0.015133660286664963,
-0.02040511928498745,
-0.01796760968863964,
-0... |
<p>I'm not sure if this is the right place to ask these kinds of questions.
I want to estimate the number of streets there are in a certain city. Any advice? How would you begin?</p>
<p>(To be precise, I want to calculate the number of streets of <a href="https://www.google.es/maps/place/Valladolid/@41.6411899,-4.7324... | g64967 | [
0.05533875524997711,
0.015706609934568405,
0.010733825154602528,
-0.013259012252092361,
-0.01413254626095295,
-0.030069051310420036,
-0.01694023609161377,
0.059041399508714676,
-0.025044312700629234,
0.00949770025908947,
-0.03452470153570175,
-0.017278483137488365,
0.03042001463472843,
0.0... |
<p>I am working with a given factor model of the form
$$y=B x +\epsilon$$
where $x$ is a random vector in $R^M$, $B$ is an $N\times M$ matrix of factor loadings, $y$ is a random vector in $R^N$ (with $N \gg M$) and $\epsilon$ is a vector of mean-zero innovations, independent of $x$. For simplicity, the innovations are... | g64968 | [
-0.042409200221300125,
0.005864530336111784,
0.002135138725861907,
0.032171767204999924,
0.0315605029463768,
-0.05800967663526535,
-0.007769264746457338,
-0.0032488182187080383,
0.0013617255026474595,
-0.012800265103578568,
-0.013016126118600368,
0.022221507504582405,
0.026408715173602104,
... |
<p>I have got a question that</p>
<p>What are the differences of the Student's T-Test, Kolmogorov-Smirnov Test (KS-Test), and the Mann-Whitney-Wilcoxon Test (MWW-Test)?</p>
<p>In the case of the T-test, the null hypothesis is μ1 = μ2, indicating that the mean of feature values for class 1 is the same as the mean of t... | g43151 | [
-0.002896211575716734,
-0.06411350518465042,
0.013636410236358643,
0.014030562713742256,
-0.019012339413166046,
-0.0064981249161064625,
0.02649671770632267,
0.04049289971590042,
-0.016127515584230423,
-0.03957784175872803,
-0.0006075678393244743,
0.04570053517818451,
0.034702807664871216,
... |
<p>I'm a journalist turned developer who hobbies in APIs and analysis of web traffic. I've always enjoyed learning about stats but as I learned, I learned that I have misapplied some basic concepts in the past. I now know a bit better, and know to doublecheck my ideas with those are smarter than me -- I'm hoping to fin... | g46384 | [
-0.03480260819196701,
0.02149173431098461,
-0.02816179022192955,
-0.04287208244204521,
-0.04470251128077507,
0.015211571007966995,
0.022174982354044914,
-0.014196719042956829,
-0.02207043394446373,
-0.06204771623015404,
0.036535292863845825,
-0.025109490379691124,
0.03440139442682266,
-0.0... |
<p>Let $t$ be a distance threshold (user-defined parameter). $X$ is a dataset containing some $p$-dimensional data-points. $L$ is a list of representative-data collected from $X$. Given the following simple algorithm:</p>
<pre><code>L = []
for each x in X:
d = min dist(x, c), for c in L
if d > t:
add x ... | g64969 | [
0.028793055564165115,
0.0170393418520689,
-0.038841236382722855,
-0.06123242899775505,
-0.03329957276582718,
-0.03311389684677124,
0.011713709682226181,
0.035328712314367294,
-0.052962955087423325,
0.0013325299369171262,
-0.06793534755706787,
0.006673044059425592,
0.06648404151201248,
-0.0... |
<p>Why does OLS estimation involve taking vertical deviations of the points to the line rather than horizontal distances?</p> | g468 | [
0.028184965252876282,
-0.005850836634635925,
-0.023498237133026123,
-0.03585590422153473,
-0.009188889525830746,
0.051154639571905136,
0.033448949456214905,
0.03022954612970352,
-0.018713772296905518,
-0.033095136284828186,
-0.012766680680215359,
-0.0019347589695826173,
0.08810217678546906,
... |
<p>In all contexts I am familiar with cross-validation it is solely used with the goal of increasing predictive accuracy. Can the logic of cross validation be extended in estimating the unbiased relationships between variables? </p>
<p>While <a href="http://dx.doi.org/10.1007/s10940-009-9077-7">this</a> paper by Richa... | g43153 | [
0.07608868926763535,
-0.020219795405864716,
0.028805354610085487,
-0.033310774713754654,
0.05189608410000801,
0.008707592263817787,
0.020687514916062355,
0.028841834515333176,
-0.011311517097055912,
0.038686931133270264,
0.036608848720788956,
-0.014791235327720642,
-0.014824273064732552,
0... |
<p>I am doing a sample size calculation for a survey and am using the formula found at the bottom of this page: <a href="http://www.raosoft.com/samplesize.html" rel="nofollow">http://www.raosoft.com/samplesize.html</a></p>
<p>In the formula, r is 'the fraction of responses that you are interested'. What is this exactl... | g64970 | [
0.027966078370809555,
0.041212912648916245,
-0.009814783930778503,
-0.041040193289518356,
0.010156030766665936,
-0.03503420203924179,
0.03875294327735901,
0.019146068021655083,
-0.019382599741220474,
-0.040714431554079056,
0.025180695578455925,
0.018806004896759987,
0.01653202809393406,
-0... |
<p>I have a binary sequence such as <code>11111011011110101100000000000100101011011111101111100000000000011010100000010000000011101111</code></p>
<p>Where clusters of mostly 1's are followed by a larger number of zeros, like in the picture below (black stands for 1):</p>
<p><img src="http://i.stack.imgur.com/i0UdS.jp... | g39519 | [
-0.04401799291372299,
0.01082712970674038,
0.00919325090944767,
-0.03893823176622391,
0.013979547657072544,
-0.07707825303077698,
0.01615286059677601,
0.04298512637615204,
-0.0002000305976253003,
-0.023439807817339897,
-0.03509945794939995,
0.014820330776274204,
0.04853951185941696,
0.0186... |
<p>I have a question:</p>
<blockquote>
<p>Is it true that $$P((-z \leq Z \leq z) = \alpha = 2(P(Z \leq z) = \alpha/2)$$ by symmetry?</p>
</blockquote>
<p>So you really only need to find one value of $z$?</p> | g23336 | [
0.0005936894449405372,
0.058881860226392746,
-0.013843332417309284,
0.0001070210782927461,
0.074581079185009,
-0.04614297300577164,
0.05853552743792534,
0.056359875947237015,
-0.019717611372470856,
-0.014892452396452427,
-0.055996354669332504,
0.023218326270580292,
-0.011798386462032795,
0... |
<p>I was wondering whether it's me mis-remembering something or is there a dimensionless measure of dispersion calculated as: range/(mean or median). Where range is a difference between max and min values.</p>
<p>P.S. Could this be called "relative range"?</p> | g64971 | [
-0.036015428602695465,
-0.07436282932758331,
-0.01874774508178234,
-0.05758657678961754,
-0.039621587842702866,
0.006233961787074804,
-0.05530422180891037,
0.0213986337184906,
-0.0796329528093338,
-0.04169367626309395,
-0.006238652393221855,
0.025925595313310623,
0.07198745757341385,
0.002... |
<p>The generalized hyperbolic distribution is said to have semi-heavy tails. I know, that heavy tails means, that the tails are not exponentially bounded, or it has heavier tails than the normal distribution. The german wikipedia connects this to the excess function and knows a medium-tailed distribution. I looked at g... | g23337 | [
0.048902273178100586,
0.05322488397359848,
-0.008591894060373306,
0.011435193940997124,
-0.00923518929630518,
0.00022812535462435335,
0.03085024654865265,
-0.01196697074919939,
-0.01940097287297249,
-0.02272140234708786,
-0.04586533084511757,
0.03294362500309944,
-0.00013298317207954824,
-... |
<p>The log-like likelihood values that are computed when I do a regression (by for instance eviews), are they comparable for different estimation techniques, specifically OLS and Maximum Likelihood? My intuition is that they are comparable when ML is done with a normal distribution, because I think that then the likeli... | g64972 | [
0.023842807859182358,
-0.09011435508728027,
0.00039806088898330927,
-0.04135822504758835,
-0.05571940913796425,
-0.00796396192163229,
0.016472727060317993,
0.019530901685357094,
-0.0469382219016552,
-0.012765887193381786,
-0.014753073453903198,
-0.0012051570229232311,
0.07736962288618088,
... |
<p>Today i stumbled upon an filtering algorithm which as final step it says that it</p>
<blockquote>
<p>scale the output matrix so it will have the same stddev and
mean as the input matrix.</p>
</blockquote>
<p>Is that possible?</p> | g64973 | [
-0.004832196049392223,
0.036434318870306015,
0.013320080935955048,
-0.03824976459145546,
0.009478475898504257,
-0.06822680681943893,
-0.026426345109939575,
0.016127007082104683,
-0.05085053667426109,
0.03419037163257599,
-0.013430885039269924,
0.06050504744052887,
0.04907776787877083,
-0.0... |
<p>If you roll 5 standard 6 sided dies, what's the probability that you will get at least three 2s?</p>
<p>I imagine it would be 1 - P(0 twos) - P(1 two) - P(2 twos), but I don't know how to calculate the probability of these.</p> | g49712 | [
-0.013603894039988518,
0.005538619123399258,
-0.0014582275180146098,
-0.002400878816843033,
0.01272257324308157,
-0.0281946063041687,
0.003858076874166727,
-0.006773187313228846,
-0.03597898408770561,
-0.02907431870698929,
-0.05566705763339996,
0.016951870173215866,
0.03784369304776192,
-0... |
<p>I'm trying to show that the probability that two vectors are similar to each other increases as the number of dimensions decreases. I define similarity between two vectors $a = [a_1, a_2, ..., a_n]$ and $b = [b_1, b_2, ... b_n]$ as each dimension in vector $a$ being in a vicinity of its corresponding dimension in ve... | g23338 | [
0.02388819307088852,
-0.009129337966442108,
0.014360977336764336,
-0.04436136409640312,
-0.0505993589758873,
0.05153857171535492,
0.009580135345458984,
-0.03237851336598396,
-0.07749266922473907,
-0.02190595306456089,
0.02294047176837921,
0.022856133058667183,
0.053388938307762146,
0.02741... |
<p>I would like to know how to, given a data set, obtain the following:</p>
<p>1/ The parametric probability density function that best explains the data</p>
<p>2/ The parameter values of such pdf</p>
<p>Thanks
Jonny</p> | g49713 | [
0.02005508542060852,
0.02737419493496418,
-0.025289887562394142,
-0.05981849133968353,
0.011558812111616135,
0.0013174534542486072,
-0.009932177141308784,
-0.007162983529269695,
-0.08159076422452927,
0.0009792710188776255,
-0.0030517098493874073,
-0.01403125748038292,
0.06286589056253433,
... |
<p>I'm analysing data from our experiment. We had participants in 4 groups, each participant was measured 4 times. We measured cortisol in saliva, so it leads us to the linear mixed models, because the individual cortisol levels have different slopes.
I have fitted following model:</p>
<pre><code>lmer1 <- lmer(Cort... | g64974 | [
-0.002225385280326009,
-0.058928366750478745,
-0.002523641800507903,
-0.04654070362448692,
0.06977679580450058,
0.010827130638062954,
0.050286173820495605,
-0.026674294844269753,
-0.05805588513612747,
-0.02216426469385624,
-0.015466997399926186,
0.06070117652416229,
-0.00881990510970354,
0... |
<p>I am looking for a method to detect sequences within univariate discrete data without specifying the length of the sequence or the exact nature of the sequence beforehand (see e.g. <a href="http://en.wikipedia.org/wiki/Sequence_mining" rel="nofollow">Wikipedia - Sequence Mining</a>)</p>
<p>Here is example data</p>
... | g49714 | [
0.0018348053563386202,
-0.009493331424891949,
0.0024923449382185936,
-0.05908700451254845,
-0.006000909022986889,
-0.09968381375074387,
0.012564975768327713,
-0.03746034950017929,
-0.042175889015197754,
-0.03371540829539299,
-0.014240357093513012,
-0.01834843121469021,
0.03502015396952629,
... |
<p>I am working on a simulation. I am going to extract a series of normally distributed values from a distribution $N(x,s)$ whose mean $x$ and variance $s$ is known. I want to pretend that such distribution $N(x,s)$ is a latent causal variable that determinates a response ordinal variable $O$ which is in a known range ... | g64975 | [
0.018051814287900925,
-0.03531765937805176,
-0.021412724629044533,
-0.10284790396690369,
-0.03757443651556969,
-0.042456090450286865,
0.008138523437082767,
-0.005803585518151522,
0.012693874537944794,
-0.04129262641072273,
-0.022182701155543327,
0.020244810730218887,
0.04338601976633072,
0... |
<p><img src="http://i.stack.imgur.com/kRbNV.jpg" alt="enter image description here"></p>
<p>I am not familiar with the change-of-variable technique that the question refers to. Does anyone have an idea what is meant and how one should go about doing it?</p> | g23340 | [
-0.025739410892128944,
-0.020283838734030724,
0.011187775991857052,
-0.045771464705467224,
-0.015814367681741714,
-0.054612115025520325,
-0.005952088627964258,
-0.010477634146809578,
-0.03106682375073433,
0.0153416208922863,
-0.007675833534449339,
0.047105737030506134,
0.07282590866088867,
... |
<p>I have data from questionnaire from school. First question is study program (only 2 programs) and next 35 questions are various questions (influence of friends etc.)</p>
<p>Possible answers for 35 questions are "definitely yes", "mostly yes", "mostly no" and "definitely no". Some of data contains missing values.</p... | g64976 | [
0.049142830073833466,
-0.01888568513095379,
-0.007852637208998203,
0.013901722617447376,
0.0012451737420633435,
0.03103211335837841,
-0.006187631282955408,
0.017665093764662743,
-0.04055015742778778,
-0.02507968060672283,
-0.03168589621782303,
0.00844862312078476,
0.05944745987653732,
0.02... |
<p>I am looking through <a href="http://rads.stackoverflow.com/amzn/click/1441926135" rel="nofollow">Time Series Analysis: With Applications in R</a> (my first exposure to time series) and refreshing summations. </p>
<p><em>I.</em>
When given the following rule:</p>
<p>COV[$\sum_{i=1}^{m} c_{i}Y_{t_{i}},\sum_{j=1}^{... | g46387 | [
-0.008508441038429737,
0.00394251337274909,
-0.024187589064240456,
-0.03935539349913597,
0.012541264295578003,
-0.048979487270116806,
0.07408429682254791,
-0.009808121249079704,
-0.06915128231048584,
0.06985305994749069,
-0.024124767631292343,
0.0411822646856308,
0.07650977373123169,
0.029... |
<p>I want to measure a moderation effect between 3 continuous variable in an intervention study. I am using scores from self-report measures of masculinity, emotionality, and psychological distress. The idea is that emotionality will be manipulated via an experimental intervention designed to increase emotionality, and... | g64977 | [
-0.022354230284690857,
-0.06518480181694031,
-0.019533051177859306,
-0.09121710062026978,
0.0015225675888359547,
0.006121281534433365,
-0.006817909888923168,
0.06007338687777519,
-0.010666333138942719,
0.014722864143550396,
-0.0073639871552586555,
0.025353970006108284,
-0.013234448619186878,... |
<p>I have a group of correlation coefficients (more than two). They are all dependent on one variable A in the form of r_A1, r_A2, r_A3....r_Ak, where 1, 2 ...k denote other variables; they all have the same sample size. </p>
<p>My question is: what statistics should I use when I want to know whether any one of the co... | g64978 | [
-0.010556547902524471,
-0.03387941047549248,
-0.0016537706833332777,
-0.04877067357301712,
-0.0038360136095434427,
-0.05484002083539963,
0.04686213284730911,
-0.0026224181056022644,
-0.019682751968503,
-0.028270067647099495,
-0.010481233708560467,
0.03817657753825188,
0.003230334958061576,
... |
<p>Is there some restriction to parameters $( \alpha , \beta)$ that makes the beta distribution concave down? Bell-shaped like e.g. a normal?</p>
<p>For example, the cases in purple and black, but not the red green or blue cases:</p>
<p><img src="http://i.stack.imgur.com/lnZk2.png" alt="enter image description here">... | g64979 | [
0.03883285075426102,
0.023839619010686874,
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0.002120070857927203,
0.01824765093624592,
0.063... |
<p>How can "weights" be given to different samples according to their relative importance while using Gradient boosted decision trees for classification? How does the <code>R</code> package <code>gbm</code> do this?</p> | g64980 | [
-0.003744988702237606,
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0.03609161078929901,
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<p>I am trying to use the "car" command in "cts package" in R program and I see the "scale" parameter there. I wonder whether this can be assumed to be equivalent to time intervals for time series forecasting.
For example, the code is like this:</p>
<pre><code>car(x, y=NULL, scale = 1.5, order = 3, ctrl=car_control()... | g64981 | [
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0.0190415158867836,
0.004851164761930704,
0.07337336242198944,
0.0... |
<p>I'm about to get my PhD. My background is in engineering and applied mathematics. My research in statistical & machine learning methods for biological applications (without being too specific). </p>
<p>I love mathematics and doing research, but I'm astoundingly terrible at politics and I think I have 0 chance o... | g23344 | [
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<p>For binary classification problems where the data is highly imbalanced, i.e. much more negative samples than positive samples, it is recommended to evaluate the performance of a classifier using the ROC curve because it does not depend on the actual ratio between positive and negative class (see e.g. <a href="http:/... | g392 | [
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<p>I have a short question about Monte Carlo integration with Metropolis sampling. I have a continuous state space, but only certain parts of this state space are valid. It is possible that the transition function can suggest a move to an invalid part of the state space, and the jump should be obviously rejected. Howev... | g64982 | [
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<p>Assume I have 400 students (that's in a big university) that have to do a computer science project, and that they have to work alone (no group of students). An example of project could be let "implementing a fast fourier transform algorithm in fortran" (I know, that doesn't sound sexy but that makes my question sim... | g43168 | [
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<p>I'm building a text classifier using the naive Bayes formula. I'm still early in the development, but I already see a problem with my technique and I was wondering if you guys would have idea that would help me solve this problem.</p>
<p>What I want to do is score texts to order them from the more likely to be in c... | g64983 | [
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... |
<p>$$\frac{e^{-(y-θx)^2/2x^2) -x/λ}}{(λ\sqrt{2πx^2})}$$</p>
<p>This is the joint distribution function.</p>
<p>a)I have to find the marginal function of $X$ and $Y|X$.
Now the $X\sim \text{Exp}(1/λ)$ and $Y|X\sim N(θx;x^2)$</p>
<p>b)Then, find the MLE for $λ$ and $θ$.<br>
For $λ$ we have:
$\cal{L}= \prod \left[e^{(\... | g64984 | [
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... |
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