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What is the rationale, if any, to use Discriminant Analysis (DA) on the results of a clustering algorithm like k-means, as I see it from time to time in the literature (essentially on clinical subtyping of mental disorders)?
It is generally not recommended to test for group differences on the variables that were used d... |
I have been looking at analyst job postings and one of the most common requirement is experience of SAS.
Unless your organisation currently uses SAS, how can you train as a SAS user?
What programming language would be equivalent to SAS that employers might be happy to accept?
|
I have a biometric system that outputs a distribution of scores that resembles a Gaussian distribution (similar to the example graph in the following link: LINK). My point of confusion is how I calculate the False Acceptance Rate. How does threshold factor into the whole problem?
|
(I'm a newbie at stats. I'm a mathematician and a programmer and I'm trying to build something like a naive Bayesian spam filter.)
I've noticed in many places that people tend to break down the denominator in the equation from Bayes' Theorem. So instead of this:
$\frac{P(A|B)\cdot P(B)}{P(A)}$
We are presented with thi... |
I have a fairly larege file 100M rows and 30 columns or so on which I would like to run multiple regressions. I have specialized code to run the regressions on the entire file, but what I would like to do is draw random samples from the file and run them in R.
The strategy is:
randomly sample N rows from ... |
I measured response variable $Y$ at three levels of factor $A$ and four levels of factor $B$, $n=6$ reps/treatment. Results include
$A$ has strong effects on $Y$.
$B$ has no effect on $Y$
There is no $A*B$ interaction
I would like to report all three results (the second two are actually more interesting than the firs... |
I have programmed a logistic regression using the IRLS algorithm. I would like to apply a LASSO penalization in order to automatically select the right features. At each iteration, the following is solved:
$$\mathbf{\left(X^TWX\right) \delta\hat\beta=X^T\left(y-p\right)}$$
Let $\lambda$ be a non-negative real number. I... |
While most of the tests for normality help for continous variables, is there a way to test the normality assumptions for binary variables.
From what i've read on wiki, the K-S test can be applied for continous variables. How do we perform normality tests for binary (or even categorical variables)?
|
I have a binary variable (which takes values 0,1). I have about 100k records of it. How do I determine if it follows the binomial distribution?
(I'm bascially trying to test for normality. And, if the data is not normal, I might have to apply a transformation to get the variable into a binomial distribution.)
Hey, tha... |
I started to do Monte Carlo in R as a hobby, but eventually a financial analyst advised to migrate to Matlab.
I'm an experienced software developer.
but a Monte Carlo beginner.
I want to construct static models with sensitivity analysis, later dynamic models.
Need good libraries/ algorithms that guide me.
To me seems t... |
I see the concept of 'exchangeability' being used in different contexts (e.g., bayesian models) but I have never understood the term very well.
What does this concept mean?
Under what circumstances is this concept invoked and why?
|
The Marascuilo procedure as described here seems to be a test that addresses the issue of multiple comparisons for proportions when you want to test which specific proportions are different from each other after rejecting the null in an overall chi-square test.
However, I am not very familiar with this test. So, my que... |
I would like to perform reversible jump on a network model, but before arriving there, I'm wondering if there are any R packages which support reversible jump for a user specified generalized linear model or spatial-GLM?
Something as simple as an RJMCMC procedure (in R) for the selection of predictors in a logistic reg... |
When programming in R, I've used the multicore package a few times. However, I've never seen a statement about how it handles it's random numbers. When I use openMP with C, I'm careful to use a proper parallel RNG, but with R I've assume that something sensible happens. Can anyone confirm that something sensible does h... |
I have 3 factors
factor1 (treatment) with 2 levels (control, stress)
factor2 (Variates) with 12 Levels (Var1, Var2,....Var12)
factor3 (Time) with 12 levels (Week1, Week2,..., Week12)
The treatment has 3 replicates for control and 6 replicates for stress.
Would it be unbalanced Design?
What design would you suggest in ... |
Which inter-rater reliability methods are most appropriate for ordinal or interval data?
I believe that "Joint probability of agreement" or "Kappa" are designed for nominal data. Whilst "Pearson" and "Spearman" can be used, they are mainly used for two raters (although they can be used for more than two raters).
What o... |
I've seen various theoretical treatments of graphics, such as the Grammar of Graphics. But I have seen nothing equivalent with regards to tables. Over the while I have developed an informal model of good practice in table design.
However, I'd like to be able to provide a good reference to students.
The APA Style Manua... |
In a multiple linear regression, why is it possible to have a highly significant F statistic (p<.001) but have very high p-values on all the regressor's t tests?
In my model, there are 10 regressors. One has a p-value of 0.1 and the rest are above 0.9
For dealing with this problem see the follow-up question.
|
I've got a model that I've developed in R, but also need to express in SAS. It's a double GLM, that is, I fit both the mean and (log-)variance as linear combinations of the predictors:
$E(Y) = X_1'b_1$
$\log V(Y) = X_2'b_2$
where Y has a normal distribution, $X_1$ and $X_2$ are the vectors of independent variables, and... |
Can anyone report on their experience with an adaptive kernel density estimator?
(There are many synonyms:
adaptive | variable | variable-width, KDE | histogram | interpolator ...)
Variable kernel density estimation
says "we vary the width of the kernel in different regions of the sample space.
There are two methods ..... |
I have SPSS output for a logistic regression model. The output reports two measures for the model fit, Cox & Snell and Nagelkerke.
So as a rule of thumb, which of these $R^²$ measures would you report as the model fit?
Or, which of these fit indices is the one that is usually reported in journals?
Some Background: The... |
In a multiple linear regression with highly correlated regressors, what is the best strategy to use? Is it a legitimate approach to add the product of all the correlated regressors?
|
I would like to apply KDE to inventory replenishment, but I am not sure how to use the analysis to predict future sales based on past sales. Given a set of data and having applied KDE to it (probably using a Gaussian distribution), how do I make a prediction about the future?
Thanks for any help! Please let me know if... |
I've got a data table like:
ID Low Color Med Color High Color
1 234 123 324
2 4 432 3423
The rows are widgets, the columns are color levels. Would you call this table "widgets by color level" or "color levels by widget"?
|
I have a dataset asking people whether they have been to a certain places (e.g. A, B, C, D), and they can make more than one choice, then a specimen is taken from their nose to see if they are infected with some disease.
I need to find out the relative risk of getting infected for one going to a certain place, I can on... |
I am trying to calculate the relative risk for being tested as positive for people aged >25 or <=25, and here is the result.
$data
Negative Positive Total
>25 115 11 126
<=25 117 3 120
Total 232 14 246
$measure
risk ratio with 95% C.I.
estimate ... |
In a problem I am working on, I have two random variables, X and Y. I need to figure out how closely correlated the two of them are, but they are of different dimensions. The rank of the row space of X is 4350, and the rank of the row space of Y is substantially larger, in the tens of thousands. Both X and Y have the s... |
I'm wondering about this question:
short version:
how to adequately compare the effect of a reclassification of the same subjects on survival
long version:
I have one cancer cohort that was sorted into TNM classes long time ago. The definition of the classes has now been updated and I like to know if, say, class 1 of t... |
Currently I have to analyze approximately 20M records and build prediction models. So far I have tried out Statistica, SPSS, RapidMiner and R. Among these Statistica seems to be most suitable to deal with data mining and RapidMiner user interface is also very handy but it seems that Statistica, RapidMiner and SPSS are ... |
Could anyone give me hints as to a model framework that can be used in the following setting:
The outcome A is dichotomous. I want to investigate the effect of a continuous variable B and a continous variable C on A in a longitudinal setting. So far so good.
The problem is that C depends on B, in that values of B abo... |
It seems to me that rather than using non robust
estimation methods with robust standard errors it would be better to use
robust estimation from the outset. I wonder what other people think.
|
Does X (hazard) variable in Cox proportional hazard regression analysis always have to be time? If not, could you provide an example, please?
Can age of cancer patient be a hazard variable? If so, can it be interpreted as the risk of getting cancer at a certain age? Would Cox regression be a legitimate analysis to stud... |
I want to calculate the probability distribution for the total of a combination of dice.
I remember that the probability of is the number of combinations that total that number over the total number of combinations (assuming the dice have a uniform distribution).
What are the formulas for
The number of combinations ... |
I have a simple time series with 5-10 data points per data set at regular intervals. I am wondering what is the best way to determine whether two data sets are different. Should i try t-tests on each data point, or look at the area under the curves or is there some kind of multivariate model that would work better?
|
I have a logistic regression (in SAS, for reference) with continuous and categorical predictors (with reference coding), and an interaction term between one of each type (assume for now that the categorical variable in question has three response levels, reference coded to $c_1$ and $c_2$):
$logit(p) = a + (continuous ... |
From the output of a logistic regression in JMP, I read about two binary variables:
Var1 estimate -0.1007384
Var2 estimate 0.21528927
and then
Odds ratio for Var1 lev1/lev2 1.2232078 reciprocal 0.8175225
Odds ratio for Var2 lev1/lev2 0.6501329 reciprocal 1.5381471
Now I obtain 1.2232078 as exp(2*0.1007384), and simi... |
I'm trying to evaluate a path dependent function, $f(r_t)$, on a Cox-Ingersoll-Ross process:
$$dr_t = \theta (\mu - r_t)dt + \sigma \sqrt r_t dW_t$$
by Monte Carlo simulation.
Could anyone suggest and explain any effective variance reduction techniques that could be used on this process? E.g. importance sampling, stra... |
Suppose we need to take an action on a population with income (x) more than $5,000. Income is not observed directly.
Should we use logistic regression to estimate x, or should we use logistic regression to estimate the probability of x>5000 directly? (What are the drawbacks/advantage of the methods?)
Edit: Yes - by log... |
I have to analyze a factorial design with five factors (one of them nested in another one) and numeric responses. I would like to perform a nonparametric ANOVA, but of course I can't use neither Kruskall Wallis nor Friedman test (I have replicated measures). Is there a command or a code in R that could help me?
Thank y... |
I have a sample set of values that were taken over a period of time. However, the delta time between each sample is different.
Do I need to account for the different time deltas in the std-dev?
Is std-dev even appropriate for this kind of data?
More info...
The data are temperature samples.
The time range is from 1 ho... |
Problem:
I am parameterizing distributions for use as a priors and data in a Bayesian meta-analysis. The data are provided in the literature as summary statistics, almost exclusively assumed to be normally distributed (although none of the variables can be < 0, some are ratios, some are mass, and etc.).
I have come ac... |
I would like to project the data in this graph for at least 4 or 5 periods. Unfortunately, that won't be possible with a moving average. A regression will result in negative values after the 3rd period. What are my forecasting options?
Basically, what i'm trying to do, is predict where the boomer hump is gonna be based... |
I have a univariate data set that's approximately normally distributed. I am happy to assume that the population is normally distributed, and I'd like to estimate the mean and variance of the population.
My textbook suggests (as I understand it) that since my sample size is large (1000's of data points), it is reasonab... |
I have a two part question;
First Part:
I have an urn with 20 balls, 2 of those balls are purple, and I pull out 6 balls at random. I witness 100 realizations of this process.
Given the observed frequency at which I drew purple balls, how do I determine if I am really pulling balls out at random? Also given that there... |
Suppose one has two independent samples from the same population, and different methods were used on the two samples to derive point estimate and confidence intervals. In trivial cases a sensible person would just pool the two samples and use one method to do the analysis, but let's suppose for the moment that differen... |
I have a multivariate regression, which includes interactions. For example, to get the estimate of the treatment effect for the poorest quintile I need to add the coefficients from the treatment regressor to the coefficient from the interaction variable (which interacts treatment and quintile 1). When adding two coeffi... |
I have 3 observers that each take 2 measurements (length and weight) on 100 individuals; these procedures are repeated once (i.e., the same measurements are taken on the same 100 individuals by the same 3 observers), so that the data set is duplicated (i.e., early reading and late reading).
What is the best way to fi... |
Could anyone suggest some statistical measures to describe the distribution of a dendrogram? If I have two dendrograms, how could can I quantify their structural differences?
|
Background:
I'm a junior researcher at an institute dealing with regional issues, particularly involving drug policy. Almost two years ago, one of our senior researchers began collecting arrest data about a nearby large city. He had been transcribing newspaper police blotter by hand until I joined a year and change ago... |
What is the meaning of $\|a\|_p=\left(\sum _{i=1}^n \left|a_i(t)\right|{}^p\right){}^{\frac{1}{p}}$?
This formula is called out on the fifth page of An Improved Data Stream Summary: The Count-Min Sketch and its Applications (which can be found here). I'm implementing the Count-Min Sketch and can understand the basic co... |
Hierarchical clustering can be represented by a dendrogram. Cutting a dendrogram at a certain level gives a set of clusters. Cutting at another level gives another set of clusters. How would you pick where to cut the dendrogram? Is there something we could consider an optimal point? If I look at a dendrogram across tim... |
I'm interested in exploring statistical models (or modifications thereof) designed to handle a specific type of problem. Due to my ignorance of statistical terminology, I can only describe this type of problem by (contrived) examples:
Suppose we're interested in estimating the likelihood that a given cell phone custome... |
When plotting a boxplot with python matplotblib, the lines halfway the plot is the median of the distribution.
Is there a possibility to instead have the line at the average. Or to plot it next to it in a different style.
Also, because it is common for the line to be the median, will it really confuse my readers if I m... |
I am trying to understand a published analysis. This is the data of interest:
D1>0 D1<0
D2>0 7 2 9
D2<0 9 15 24
total 16 17 33
The author notes that 17/33 is 51.5% and states:
"we expect about 50% of the D1's to be negative, and that is what we actually observe here (z=.08, p... |
I am newbee and i am trying with functional data analysis. I have a 8x11 matrix data, how can i input into R as an object in this form:
$hgtm
boy01 boy02 boy03 boy04 boy05
1 81.3 76.2 76.8 74.1 74.2
1.25 84.2 80.4 79.8 78.4 76.3
1.5 86.4 83.2 82.6 82.6 78.3
1.75 88.9 85.4 84.7 85.4 80.... |
I posted this question earlier and am rewriting it in hopes of getting some guidance. I am using a weighted regression (after propensity score matching) to obtain estimates of the effects of a treatment (treat) on an outcome for different income quintiles. I include interactions of the quintiles and the treatment in th... |
I plotted below the standarized results of:
RAND()
RAND() * RAND()
...
RAND() * RAND() * RAND() * RAND() * RAND() * RAND()
It seems that the results are getting to zero, is that because you're multiplying a bunch of numbers close to zero together, or is there another explanation?
EDIT
There is no real motivation... |
I have a data set of 100 geographic regions for which the unemployment rate has been observed during the last 9 years. Now, I want to simulate/forecast from this data the next year unemployment rate for all the 100 regions.
What would be a suitable approach? I was thinking to use an auto-regressive mixed effect model,... |
When using cluster analysis on a data set to group similar cases, one needs to choose among a large number of clustering methods and measures of distance. Sometimes, one choice might influence the other, but there are many possible combinations of methods.
Does anyone have any recommendations on how to choose among ... |
I'd like to use Bayes' Theorem on data obtained through a small random sample, and I want to use Agresti-Coull (or any other alternative technique) to know how big the uncertainty is.
Here is Bayes' Theorem:
$P(A|B) = \frac{P(B|A)\cdot P(A)}{P(B)}$
Now, all the data I have on this system is obtained from small random s... |
How is it possible to calculate Pearson/Spearman correlation of more than two judges in MATLAB?
Thanks.
|
According to Microsoft Excel Help:
VAR uses the following formula:
where x is the sample mean
AVERAGE(number1,number2,…) and n is
the sample size.
Shouldn't it be n, rather than n - 1, in the denominator?
|
What's the best way to approximate $Pr[n \leq X \leq m]$ for two given integers $m,n$ when you know the mean $\mu$, variance $\sigma^2$, skewness $\gamma_1$ and excess kurtosis $\gamma_2$ of a discrete distribution $X$, and it is clear from the (non-zero) measures of shape $\gamma_1$ and $\gamma_2$ that a normal approx... |
I get this question frequently enough in my statistics consulting work, that I thought I'd post it here. I have an answer, which is posted below, but I was keen to hear what others have to say.
Question: If you have two variables that are not normally distributed, should you use Spearman's rho for the correlation?
|
In several different contexts we invoke the central limit theorem to justify whatever statistical method we want to adopt (e.g., approximate the binomial distribution by a normal distribution). I understand the technical details as to why the theorem is true but it just now occurred to me that I do not really understan... |
I have sampled a number of $x$ values from a normal distribution with mean 0 and sd 0.2. I then transformed these $x$ values to $y$ values using the formula $y = e^x/(e^x + 1)$. I know that the $y$ values will have a mean of 0.5 and all lie between 0 and 1.
Do these y values fit some common distribution?
Is there a ... |
I need to write a program to find the average GPS point from a population of points.
In practice the following happens:
Each month a person records a GPS point of the same static asset.
Because of the nature of GPS, these points differ slightly each month.
Sometimes the person makes a mistake and records the wrong ass... |
I am discovering the marvellous world of such called "Hidden Markov Models", also called "regime switching models".
I would like to adapt a HMM in R to detect trends and turning points. I would like to build the model as generic as possible so that I can test it on many prices.
Can anyone recommend a paper? I have see... |
This question is prompted by discussion elsewhere.
Variable kernels are often used in local regression. For example, loess is widely used and works well as a regression smoother, and is based on a kernel of variable width that adapts to data sparsity.
On the other hand, variable kernels are usually thought to lead to p... |
trying to read a large dataset in R the console displayed the follwing errors:
data <- read.csv("UserDailyStats.csv", sep=",", header=TRUE,
na.strings="-", stringsAsFactors=FALSE)
> data = data[complete.cases(data),]
> dataset <- data.frame(user_id=as.character(data[,1]),
event_date= as.character... |
In my data, the RT (gaze) of individuals (ID) is examined as a function of a visual conditions, the factor size (small, medium, large).
Base model:
print(Base <- lmer(RT ~ Size + (1|ID), data=rt), cor=F)
Random effect:
print(NoCor <- lmer(RT ~ Size + (0+Size|ID) , data=rt))
print(WithCor <- lmer(RT ~ Size + (1+Size|I... |
I'm a new R user and had just tried running friedman on non-normal and heteroscedastic data on seagrass. I am testing whether biomass is significantly different between sites across years. R (friedman function from agricolae package) returned result like this:
Friedman's Test
===============
Adjusted for ties
Value: ... |
I'm looking for an implementation of FNN (or better yet, a SOFNN as described by Forecasting Time Series by SOFNN with Reinforcement Learning). Any language, though preference is Java, C#, C++ in that order.
|
I have 6 sets of interval data each of which between 0 and 1. Each set, calculated by a computer program, is related to the degree of similarity between some sounds (pairwise).
What do you think in the best inter-rater reliability measure I can use to see how close the 6 judges are?
If I want to explain the data in eac... |
I am evaluating the effectiveness of 5 different methods to predict a particular binary outcome (call them 'Success' and 'Failure'). The data look like so:
Method Sample_Size Success Percent_Success
1 28 4 0.14
2 19 4 0.21
3 24 7... |
Suppose you had a bag with $n$ tiles, each with a letter on it. There are $n_A$ tiles with letter 'A', $n_B$ with 'B', and so on, and $n_*$ 'wildcard' tiles (we have $n = n_A + n_B + \ldots + n_Z + n_*$). Suppose you had a dictionary with a finite number of words. You pick $k$ tiles from the bag without replacement. Ho... |
I've got a dataset where someone counted birds in the breeding season over 10 years. For each year (x site), we want to see how reduced sampling might affect our ability to detect a trend. So to that end, I have simulated various datasets from the original where we cut down sampling to once every 45 days (and 60, 90,12... |
I designed a field experiment with 4 independent factors but data is not normal and heteroscedastic. Friedman test (agricolae package) from R only fits for rbd. Can anybody suggest how to analyze my data please?
|
For a unimodal distribution that is moderately skewed, we have the following empirical relationship between the mean, median and mode:
$$
\text{(Mean - Mode)}\sim 3\,\text{(Mean - Median)}
$$
How was this relationship derived?
Did Karl Pearson plot thousands of these relationships before forming this conclusion, or... |
1- How can I check if a set of data can be assumed as IID data?
I'm not so familiar with statistics, but I guess I should look at the first lag of autocorrelation for independent distribution. Have no idea about identical distribution condition!
2- It seems that I was not clear enough!
I'm trying to detect outliers in... |
Is there a term that describes what I'm trying to do below?
Also, how would you do this using something like JMP or Excel? (or do I need to code this in something like perl?)
Given this sort of data:
ID| opened | closed | quantity
--------------------------------------
1 | 2010-01-01 | 2010-01-03 | 1
2 | 2010-0... |
I am looking for a software tool (preferably open source) to draw structural equation/mixture models efficiently and prettily.
After looking into xfig and graphviz I now stick to the general vector graphics package inkscape because it seems most flexible.
I would like to poll the stat.stackexchange community: How do y... |
I've got following problem:
- We have set of N people
- We have set of K images
- Each person rates some number of images. A person might like or not like an image (these are the only two possibilites) .
- The problem is how to calculate likelihood that some person likes a particular image.
I'll give example present... |
Suppose I'm modeling a set of processes using a beta-binomial prior. I can build parameterized beta-binomial models that average over large groups of the processes to give reasonable, although coarse, priors.
$p_i \sim \beta B(n, \alpha_i, \beta_i)$ (roughly)
I know how to update those priors using observed partial da... |
I have a very simple model. This model uses data that are not given as continuous distributions, but are described by percentiles. What is the best way to sample these percentile bins, when the bins are of unequal size?
So, for example, to select the body weight for a given individual, I pick a random number between ... |
I have data from a survey comprised of several measures that used different Likert-type scaling (4-, 5-, and 6-point scales). I would like to run a principal components analysis using the data from these measures. It seems to me that I need to transform this data in some way so that the power of all items is equivale... |
I recently asked a question regarding general principles around reviewing statistics in papers. What I would now like to ask, is what particularly irritates you when reviewing a paper, i.e. what's the best way to really annoy a statistical referee!
One example per answer, please.
|
I have three variables,
1. Irrational Beliefs (Categorical)
2. Anxiety State/ Trait (Categorical)
3. Personality Traits (Categorical)
Which statistical analyses can be used?
|
I've been asked a question - if I calculate some sd, can I change one value and still keep the same sd.
The answer is simply yes. For example:
sd(c(2,3,4))
sd(c(3,4,5))
But what I wondered then is, assuming you change k values, under what rules do you change them so to always keep the same sd (is it true to ask what... |
I have 6 similarity matrices reflecting the proximity of 100 pairs of sounds. Similarity indices are in the range [0,1], with higher values indicating sounds perceived as more alike. What is the most appropriate metric I can use to estimate the inter-rater reliability between them?
Thanks a lot.
|
How does one calculate Cohen's d and confidence intervals after logit in Stata?
|
This example was taken from Mathematical Statistics : A Unified Introduction (ISBN 9780387227696), page 58, under the section 'The Principle of Least Squares'. I think my problem has more to do with algebra but since this is a statistics book, I thought I should post here...
Anyway, I need to estimate k base on this eq... |
I have two time series, series1 and series2. My aim is to find how much Series2 is different from Series1, automatically/quantitatively.
Image can be seen in its original size by clicking here.
Series1 is the expected result.
Series2 is the test/incoming series.
I am providing a histogram plot, where Series2 is repres... |
I have two years of data which looks basically like this:
Date ___ Violence Y/N? _ Number of patients
1/1/2008 ____ 0 __________ 11
2/1/2008 ____ 0 _________ 11
3/1/2008 _____1 __________ 12
4/1/2008 _____0 __________ 12
...
31/12/2009____ 0__________ 14
i.e. two years of obse... |
I want to create a bardiagram for these data in R (read from a CVS file):
Experiment_Name MetricA MetricB
Just_X 2 10
Just_X_and_Y 3 20
to have the following diagram:
I am beginner and I do not know even how to start.
|
Please see question for the background.
Following the advice of @kwak and @Andy W, I have decided to use the package plm in R to fit my model. Here an excerpt of the data df (the numbers are made up, not real data!):
reg year ur mur cl
1 1 2001 0.000698717 0.012483361 1
2 2 2001 0.008283762 ... |
Are there any tools that can format and write to external file output of principal component analysis in Stata?
I'm thinking about something that will work in similar vein to [excellent] family of estout commands.
|
I have the following R code for creating barplot:
# ... here I read cvs file
mx <- rbind(results$"AVG.P10.")
colnames(mx) <- results$"RUN"
rownames(mx) <- "AVG P"
postscript(file="avg_p_result.ps")
barplot(mx, beside=T, col=c("grey"), names.arg= results$"RUN",
cex.axis = 1.5, cex.lab=1.5)
I h... |
Imagine I have a test for a disease that returns either a positive or a negative result. I administer the test to one group twice in a single session; in another group, I administer it twice with two weeks separating the tests. The hypothesis is that the tests taken at the same time will be more consistent with each ... |
Are there standard ways of analyzing and generating "clumpy" distributions?
analyze: how clumpy is a given point cloud (in 1d, 2d, nd),
what are its clumpy coefficients?
generate or synthesize a pseudo-random cloud with coefficients C
(These are the basics for any family of distributions, e.g. normal.)
There are many... |
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