instruction stringlengths 9 38.7k |
|---|
I have 4 groups that I am comparing to a criterion. In one of my groups, all the participants answered the same on every item, i.e. there is no variance.
How do I deal with that in my ANOVA?
Also, what do I make of that in a t test I am running comparing it to a criterion since I will get no error term? If I do includ... |
I have a 200 samples from a population, and I want the p-value to test for significance. What test should I use?
Is t-test ok? How do you determine what test to use?
|
Given this joint probability distribution table
| A | B | C
X | 0.15 | 0.03 | 0.07
notX | 0.05 | 0.25 | 0.45
I've to calc the following probabilities
P(B or X) = ?
P(C or notX) = ?
So far I got this solution:
P(B or X) = 0.15 + 0.03 + 0.07 + 0.25
P(C or notX) = 0.07 + 0.45 + 0.05 + 0.25
but... |
Let's say we have the statistics given below
gender mean sd n
f 1.666667 0.5773503 3
m 4.500000 0.5773503 4
How do you perform a two-sample t-test (to see if there is a significant difference between the means of men and women in some variable) using statistics like this rather than actual data?
I couldn't find anywhe... |
Fixed effects model seems to differ from random effects model for a meta-analysis of sample correlations in terms of assumptions. What is key assumption for a fixed effect model?
|
Suppose you are given a $95 \%$ CI $(1,6)$ based on the normal distribution. Is there any easy way to find $\mu$ and $\sigma$? What if it came from a gamma distribution? Can we do this in R?
|
I have two ordinal dependent variables, each having three response levels. You can use an ordered logit or probit model for such data if you have one dependent variable. I've seen some papers about multivariate ordered regression, and wonder if there are prepackaged functions in any of the usual stats software environm... |
I would like to know the accuracy of each path in a decision tree in Matlab.
I can build a decision tree in Matlab by:
ctree = ClassificationTree.fit(X,Y)
Where X is a matrix of instances (rows are observations, columns are variables), and Y is the response variable.
Here's an example of a simple output tree:
For ex... |
I am trying to determine if simple probabilities will work for my problem or if it will be better to use (and learn about) more sophisticated methods like logistic regression.
The response variable in this problem is a binary response (0, 1). I have a number of predictor variables that are all categorical and unordere... |
I saw a method for dimensionality reduction for the squared exponential covariance function (not ARD) whereby one uses a $G\times D$ projection matrix $P$ ($G < D$, $D$ = dimension of the inputs) such that the squared distances are calculated in a lower dimensional space. E.g. the kernel function
$$K(x, x') = c \times... |
I am having a dreadful time making progress with the following problem, and would greatly appreciate any pointers you had.
The problem states that a device's risk of failure within 8 hours of activation, X, varies from day to day according to the probability density function $f(x) = 20(1-x)/9$ for $0.1 < x < 1$, and $f... |
I believe I need to run a mixed-effects ANCOVA, and I am having difficulty, presumably, because I have missing data in one of my fixed effects or an incomplete design.
I have a random grouping variable, abs.id, two categorical variables, leaf.species and cond.time, and one continuous covariate, day.
abs.id includes up ... |
I am trying to replicate a colleague's work and am moving the analysis from Stata to R. The models she employs invoke the "cluster" option within the nbreg function to cluster the standard errors.
See http://repec.org/usug2007/crse.pdf for a fairly complete description of the what and why of this option
My question is ... |
Still learning basic syntax in R. Basic example code is provided below.
I know how to call consecutive rows but what if, for example, I wanted the 1st and 3rd row? Or better yet, since that is easily called by w[-2,] in this example, what if the data set was larger and I had the need to investigate the 3rd, 5th and 8t... |
I am trying to learn a logistic regression classifier using glm on a dataset of <20 features, but lots of samples. One of the features is a very strong predictor. As a result, the trained model is predicting extreme probabilities of 1.0 and 0.0 on majority of test data. Although the model converges, I get repeated warn... |
I'm trying to reduce noise (improve separability) among groups in a data set with 26 numerical variables and 10.000 samples. Each sample is a chemical profile, with each variable indicating the quantity of some chemical constituent. Most of the variables are far from normal.
My question is: how can I test whether samp... |
How can I use "partial pooling" to shrink cells with a small sample size towards the mean in a contingency table? I am interested in the proportions within each cell with a positive response.
To clarify, I am tabulating various customer demographics survey across a range of stores. I would consider a standard contingen... |
Possible Duplicate:
Recommended books on experiment design?
I will be working with three treatments of egg replacers in bakery applications and would like to receive recommendations for the experiment design and data analysis.
|
I've been doing a bit of research into bootstrapping as I've been told one method of performing it, and this seems to differ from what I can find in other sources.
I have a sample, and want to estimate the mean or median. I generate 1000 resamples, without replacement, calculating the mean/median for each. By taking th... |
When calculating Cohen's $d$ for independent samples, you must use a pooled $SD$. However, I have seen both of these:
$$SD_{\text{pooled1}} = \sqrt{\frac{ (n_1 - 1)s_1^2 + (n_2 - 1)s_2^2}{n_1 + n_2}}$$
vs.
$$SD_{\text{pooled2}} = \sqrt{\frac{ (n_1 - 1)s_1^2 + (n_2 - 1)s_2^2}{n_1 + n_2 -2}}$$
Supporting the use of $SD_{... |
My question is regarding linear regression and non-constant variance. I've heard that even though a large data set fails a normality test, this does not necessarily mean the data is not normal. This is because the tests for normality can be 'overly' sensitive.' Thus, I've heard that, in practice, people overlook when n... |
I want to calculate coefficients to a regression that is very similar to logistic regression (Actually logistic regression with another coefficient:
$$ \frac{A}{1 + e^{- (b_0 + b_1 x_1 + b_2 x_2 + \ldots)}},$$
when $A$ could be given).
I thought of using GMM to calculate the coefficients, but I'm not sure what are th... |
So, I'm working with GWAS SNP data and want to perform several tests for association between genotype and phenotype. There are two phenotypes (case and control) and 2 or three genotypes. Most of them are Chi-squared tests with different contingency tables, $2 \times 2$ or $2 \times 3$, one of them is the Cochran-Armita... |
This is more of a data management question.
When merging several waves of a survey where the same questions were asked in multiple years -- but each time of a new sample -- should the data from a question be merged into the same variable or separate variables?
Since each wave was administered to a new sample, the uniqu... |
I have a dataset spanning several years, that I have analysed year by year (using the same glmm model code) to determine whether the random effect (random intercept) has altered over time. I have found that it has altered.
Now I am concerned that the fixed effects have also altered, which may mean that I can't compare... |
I'm trying to build a model that would describe some process of payment and distribution of payments in time. I believe that time of payment has Levy distribution with probability density function:
$ f(x,c)=\sqrt{\frac{c}{2\pi}}~~\frac{e^{ -\frac{c}{2x}}} {x^{3/2}} $
This distribution depends on parameter c which actua... |
I want to determine if there's a difference in mean p-values between two groups. In order to do this I perform a Wilcoxon's rank-sum test (the data is not normally distributed). So far, so good. Finally, I want to calculate the corresponding effect size. Unfortunately, R does not provide this. It also does not provide ... |
I know that linear regression can be thought as "the line that is vertically closest to all the points":
But there is another way to see it, by visualizing the column space, as "the projection onto the space spanned by the columns of the coefficient matrix":
My question is: in these two interpretations, what happens... |
Suppose we have a joint distribution on vector $[\mathbf{x}, y]$:
$$
p([y, \mathbf{x}] ) = \mathcal{N}\left(\begin{pmatrix} y \\ \mathbf{x}\end{pmatrix}| 0, \begin{pmatrix} k& \mathbf{v} \\ \mathbf{v}^T & K\end{pmatrix}\right),
$$
where $\mathbf{x} \in \mathbb{R}^N$, $y \in \mathbb{R}$.
And also we know distribution of... |
I am seeking a statistic measuring an estimate's reliability or stability as an alternative to the coefficient of variation (CV), also known as the relative standard error. The CV is the standard error of an estimate (proportion, mean, regression coefficient, etc.) divided by the estimate itself, usually expressed as a... |
I am measuring the change in random effect (random intercept) over time by running models such as
glmer( bull~p1+p2+p3+p4+p5+(1|school),subset=(yr=2011),data=bull, family=binomial(link=logit))
using different subset=(yr=20??) for each year. In the comments to my other question, it was stated that another way to do th... |
I have a set of data on smoking patients and heart attack on different time points for 25 countries.
How can I calculate the correlation between the smoking patients and heart attacks for each country?
My data look like this table1:
Smoking Heart Attack
Country 1988 1984 2010 1988 1984 2010... |
I have a number of multivariate observations and would like to evaluate the probability density across all variables. It is assumed that the data is normally distributed. At low numbers of variables everything works as I would expect, but moving to greater numbers results in the covariance matrix becoming non positive ... |
One naive method for approximating a normal distribution is to add together perhaps $100$ IID random variables uniformly distributed on $[0,1]$, then recenter and rescale, relying on the Central Limit Theorem. (Side note: There are more accurate methods such as the Box–Muller transform.) The sum of IID $U(0,1)$ random ... |
I'm considering using a neural network on financial time series but rather than train the network on actual data I am going to train on a model of the data which is perturbed by random noise. This being the case, I will potentially have unlimited amounts of model training data. However I don't want to generate a huge a... |
I am trying to model a queue system (via simulation) to see if I can make different work assignments to improve the overall performance (based on a number of metrics). I have historical records of past tasks which includes when they entered the system, who was assigned to perform to the task, and the service time. In... |
It seems like data visualization experts generally disapprove of gauge charts (see here: What do you call a chart that looks like a half pie chart with a needle indicating a percentage?). The primary reason is that a gauge chart has a low data-to-ink ratio.
Ever since I was exposed to these concepts (a few Tufte books)... |
The partial eta squared indicates that gender explains 5% of the variance in drugs and ethnicity explains 6% of the variance in drugs. These are small effect sizes.
I am not sure I understand this because when I look at the ANOVA table produced by SPSS it says that the Partial ETA squared for gender is .045 and for eth... |
I have collected psychophysiological data measuring the subjects' (two groups) ability to perceive vibration. A vibrating probe moves against the skin at smaller and smaller displacements, and the subject indicates when they feel the vibration. Unfortunately, at high frequencies, the probe can only move a short dista... |
Sampling with replacement $N$ items from $K$, where $N \geq K$, what is the probability that each item in $K$ is selected at least once?
For example, from $10,000$ individuals, what is the probability that every birthday is represented? (assume each birthday $p = 1/365$)
I've been using simulations to work this out, bu... |
I'm using the package 'lars' in R with the following code:
> library(lars)
> set.seed(3)
> n <- 1000
> x1 <- rnorm(n)
> x2 <- x1+rnorm(n)*0.5
> x3 <- rnorm(n)
> x4 <- rnorm(n)
> x5 <- rexp(n)
> y <- 5*x1 + 4*x2 + 2*x3 + 7*x4 + rnorm(n)
> x <- cbind(x1,x2,x3,x4,x5)
> cor(cbind(y,x))
y x1 x... |
Is there a commonly acceptable error rate for validation? As in, if the error rate is less than X %, then my machine learning method would be considered "successful".
I'm looking for something analogous to a p-value of 0.05 used for many experiments, but for cross-validation.
I would use 5% as an error rate but thats r... |
There are 26 participants who have participated in my research. Each participant treated with a lab module (Hands on Robotics Session). Now each participant will be evaluated using a rubric on scale of Excellent, Good, Fair and Poor.
For my research i want to evaluate the following questions:
Question 1
Null Hypothesis... |
Given a dataset:
x <- c(4.9958942,5.9730174,9.8642732,11.5609671,10.1178216,6.6279774,9.2441754,9.9419299,13.4710469,6.0601435,8.2095239,7.9456672,12.7039825,7.4197810,9.5928275,8.2267352,2.8314614,11.5653497,6.0828073,11.3926117,10.5403929,14.9751607,11.7647580,8.2867261,10.0291522,7.7132033,6.3337642,14.6066222,11.3... |
I have a data set that has been divided into $n$ data subsets.
I am sampling from each of these subsets and getting a tuple consisting of mean, variance, confidence and number of sampled points used.
How can I combine these results?
I do not know how other than a simple function of the number of points and their averag... |
I'm working on a survival analysis project where it would be useful to visualize everyone's followup time and event times. The data is made up of an ID, which of two possible events they had (A or B), and the time at which they had the event as well as whether or not they are interval censored. Non-censored individuals... |
I am a little bit confused by the distinction. What are the formal definition of paired and unpaired? More specifically, if I have 2 time series measuring the same quantity (e.g. vacancy rate) with slightly different underlying data, are the data paired or unpaired?
|
I've conducted an experiment in which we have registered a physiological measure (FR) of 30 participants in two different conditions. In each condition, I registered the measure in 20 time points, equally spaced in time.
To analyze the data, I'have fitted a multilevel model in R, using the nlme package. I've considere... |
On a post from the internet I've found the following expression, which I'll like to understand and to apply it on my datas.
"Because of the size difference between the largest and the smallest
metros, the data is expressed in logarithmic form so as to facilitate
comparison."[source]
|
I am reading up on orthogonal regression for possible implementation in one of my datasets. My question relates to computation of prediction errors as "mean prediction errors -MPE" or "mean absolute prediction errors-MAPE" in orthogonal regression where my dependent and independent variables (both measured in the same ... |
I am generating some Granger causality tests for various time-series. I have noticed something that appears odd. I have timeseries $A$ and $B$. Sample size is about 1500 elements in each.
$A$ and $B$ are highly correlated about 70%.
When I do a 1 ,2,or 3 lag Granger test I get p values like 0.0000000000034.
That seems ... |
I have two groups of participants. Each group contains 30 children (15 girls and 15 boys). The first group has been sampled from a population of children being raised under some kind of constitutional care, while the second group represents children living in their families.
I want to measure their social skills and co... |
I have expression values (log2) for 200 genes in two conditions treated and untreated and for each condition I have 20 replicates.
The dataset looks like this:
Gene UT1 UT2 T1 T2
DDR1 8.111795978 7.7606511867 7.9362235824 7.5974674936
RFC2 10.2418824097 9.7... |
Possible Duplicate:
The Monty Hall Problem - where does our intuition fail us?
Marliyn vos Savant on September 9, 1990 wrote that the "correct" answer to this question was to switch doors, because switching doors gave you a higher probability of winning the car (2/3 instead of 1/3).
Suppose you're on a game show, an... |
In the context of online clustering, I often find many papers talking about: "dirichlet process" and "finite/infinite mixture models".
Given that I've never used or read about dirichlet process or mixture models. Do you know any suggestions of introductory lectures or papers that are easy to understand, about that ?
|
Suppose I have $n$ data sets where each variable has the same variable types, but possibly a different number of data points. For instance, age, sex, and height, for $n$ different counties. After performing analysis (linear, logistic, Poisson, etc..) on each data set (country), how do I display information for all th... |
First, a little background:
I'm a college paintball coach and I'm trying to identify which of my players have the biggest impact on various statistics (e.g. winning percentage etc).
In order to do this I've put together a csv file with the following columns for each point that we play (you can use hockey as a mental m... |
I would like to generate a set of artificial data using another input set from which correlations between variables can be extracted. Not all variables are binary, but the data can easily be extended to be so, at the cost of increased dimensionality.
I was only able to find a method for the generation of correlated art... |
I'm currently experimenting with Gaussian processes.
I decided to use matlab + gpml (http://www.gaussianprocess.org/gpml/code/) for playing around with Gaussian processes a bit.
I'd like to do Gaussian process regression on 2d data (2d inputs and 1d output). For that I created some simple test data:
#x y z
0 0... |
Possible Duplicate:
What book would you recommend for non-statistician scientists?
Could anyone suggest a concise book/tutorial on statistics with examples. I am a biologist and need basic concepts with examples.
I have planned 10 days for this learning exercise so please keep that in mind while suggesting.
Thank y... |
My dataset contains about 12% missing data, and much of the missing data is grouped along observations (not randomly scattered or along columns). I optimized a regression method after removing the observations with large amounts of missing data (and used KNN-impute to infer the remaining missing data). I am now trying ... |
I am using the factanal function in R to conduct factor analysis. Somebody told me that I need to use Adjusted $R^2$ to get more accurate results in factor analysis. But when I looked at the option of factor analysis, I couldn't find the way to do that. Any ideas?
|
I have run a regressions relating metal revenue to a metal index in each of 25 different factories. In 24 of the factorias $R^2$ is greater than .75. In one factory the $R^2$ is .061.
Why is that $R^2$ is so low in one factory?
|
Hello fellow StackExchange users,
Preamble: I have been tasked with performing a cluster analysis (or possibly a latent class analysis, as I am pondering) to find non-overlapping groups of like subjects presenting with similar psycho-social traits, as measured in the dataset. There are a priori hypotheses about the num... |
I am a complete stranger to statistics (apart from mandatory courses in college), but lately I ran into an interesting real-world scenario.
Recently I started jogging. I take my GPS phone with me to measure time and distance. I picked a route (about 4km, but I don't know exactly) and started running. I have observed th... |
I am trying to use a function from the forecast package, seasonaldummy(), which requires a time series object as input, but I have an xts object, call it x. So first, is it correct that xts objects can not be directly passed to functions that require a ts object?
I then tried to coerce it to a ts object. I tried this b... |
I have a word representing a DNA sequence and each letter of that word is a nucleotide base (A,T,G,C). Each letter has a phred quality score. The formula used for the phred quality score is $Q=-10\log_{10} P$ where $Q$ is the phred score and $P$ the probability of that letter to be incorrect( for example, there was a ... |
How can I test whether the mean (e.g., blood pressure) of a subgroup (e.g., those who died) differs from the whole group (e.g., everyone who had the disease including those that died)?
Clearly, the first one is a subgroup of the second one.
What hypothesis test should I use?
|
I need to generate a list of random variables $\bf{x}$ subject to constraints that can be expressed in the form $\bf{E}x=b$ where $\bf{E}$ is an $m \times n $ matrix if $\bf{x}$ has $n$ entries. In all the cases I'm dealing with, $n >> m$, for example $n$ will be around 14,000 and $m$ will be 50. I'm not sure what meth... |
Is there an easy way to obtain the covariance of the parameters from a constrained regression fit?
I am using the PCLS function in the MGCV package in R to fit the constrained regression, however I am open to other approaches.
The constraint I am imposing is that the coefficients must be positive.
|
What is the difference between the Kwiatkowski–Phillips–Schmidt–Shin (KPSS) test and the augmented Dickey-Fuller (ADF) test? Are they testing the same thing? Or do we need to use them in different situations?
|
I have to represent some forecasting deviations into a chart. The problem is that I can’t find the proper way to do it. I don't know which approach to use in order fit with the data type I'm working with. The biggest is the traffic the more accurate the forecasts is. The following table represents the forecast deviatio... |
I have a certain computational biology problem I wish to model. Say I have a vector $\vec{f}$ that yields $\vec{p}$, of which the explicit form amounts to picking $\vec{p}$ as an eigenvector from an eigenvalue-problem with the largest associated eigenvalue.
$\vec{p}$ is a probability vector, i.e. its components sum to... |
My dataset contains variables of two levels, say individuals and regions.
Each level has features. Note that the level2 features are repeated within each level2_ID.
example_data <- data.frame(level1_ID = c(1, 2, 3, 4, 5),
level1_depend = c(17, 32, 27, 30, 31),
leve... |
I'm using k-means to cluster sentences according to the part-of-speech tags of the words in a sentence, and I have a nice, easy to understand visualization of the result, but I'm struggling to find a good method to quantify the result.
My starting point is a paper by Dowty which postulates that there is a certain fixed... |
Assuming I have a data set of known size, and there is one object that I want to test for being in an approximately uniform distributed region of the data set.
For the query object, I know the $k$ nearest neighbors and the associated distances. If the data set is uniform there, the distances should be $c\cdot\chi(d)$ d... |
Repeatedly rolling a six sided die four times and summing the highest three results gives you a distribution with what mean and standard deviation?
I've only taken AP statistics, but I would like to learn how to do this.
|
We have a multivariate normal vector ${\boldsymbol Y} \sim \mathcal{N}(\boldsymbol\mu, \Sigma)$. Consider partitioning $\boldsymbol\mu$ and ${\boldsymbol Y}$ into
$$\boldsymbol\mu
=
\begin{bmatrix}
\boldsymbol\mu_1 \\
\boldsymbol\mu_2
\end{bmatrix}
$$
$${\boldsymbol Y}=\begin{bmatrix}{\boldsymbol y}_1 \\
{\boldsymbo... |
I recently collected some survey data where people made a series of judgments about others' actions and their willingness to make some choice about that action.
Looking at the zero-order correlations, I see that some of the judgments are significantly correlated with the choices of the participant, whereas some others ... |
I have heard the term "orthogonal * validation" used recently. It was used in the context of experimental platform testing. What does this mean? I cannot find anything on it in literature or Wikipedia.
|
I have a given data set $D = \{ x_i, y_i \}_{i=1}^n$ for a regression problem. When I plot the data, it looks like there is an underlying parabola (2nd
order linear model) and some outliers.
I want to design an approach using a probabilistic model with a latent binary variable $\{ 0,1 \}$ indicating whether a data poin... |
I'm programming a web tool (="I'm a stats ignoramous who drifted here from stackoverflow.com") that allows scientists to enter predictions about the 5-number-summary stats for a variable. Entry is done using the UI-metaphor of a box-plot.
I'd like to allow scientists to visualize their input as a PDF/CDF, but I have to... |
I'm a journalist, and I am trying to work out whether hospitals that are in political districts with low majorities (i.e. where the political representative is fighting hard for his or her seat) are more likely to get extra funding.
In other words, do hospitals that have received extra funding tend to be in districts ... |
I am currently analyzing a 34-item standardized survey on Physics expectations. I gathered data from 104 female respondents from a certain school. The survey's supporting literature said that the survey measures 6 specific dimensions, with each dimension corresponding to 5-6 items. My professor asked me to conduct SPSS... |
I'm currently studying for an Experimental Design exam. I feel like I'm missing something quite fundamental...
I've attached a minimal example to illustrate my confusion at https://gist.github.com/2942913
We were asked to compare the treatment and sum dummy coding systems.
It was pointed out that with the treatment sy... |
The Kappa ($\kappa$) statistic was introduced in 1960 by Cohen [1] to measure agreement between two raters. Its variance, however, had been a source of contradictions for quite a some time.
My question is about which is the best variance calculation to be used with large samples. I am inclined to believe the one test... |
Suppose we test the Pearson correlation between variable $x$ and $y$ in groups $A$ and $B$. Is it possible for the $(x,y)$ correlation to be significant in each of $A$ and $B$, but non-significant when data from both groups are combined? In this case, could you please provide an explanation for that.
|
I am having serious problems understanding the type of design I have, I would appreciate any help you can give me to understand it:
I have 324 data points, and four factors:
epoch factor, with three levels.
altitudinal floor factor, with three levels.
site factor, with nine levels.
time factor, with three levels.
I h... |
The Likert scale I am analyzing has both positive and negative questions, but all the items are answered with 4 - strongly agree, 3 - agree, 2 - disagree and 4 - strongly disagree. For analysis, should I make the weight of the answers the same?
For example, if the statement is positive, then 4 must be given to strongl... |
Please advise how best to approach the following;
I have a trend following trading signal comprising a trailing simple moving average over n data points. The data is stationary. Currently i calculate a z-score based on the n data points, and judge the signal strength of the newest data point as the value of its z-sco... |
I have RNA-seq data from 9 samples and around 15,000 genes. I know that these 9 samples consist of varying proportions of two cell types, each with their own expression profile. I am using non-negative matrix factorization with a rank of 2 to determine the cell-type ratios in each sample. In other words, I use NMF t... |
I am reviewing my time series knowledge and looking for a document that has the commonly-used time series tests, what they are used for, how to use them, etc. e.g. Augmented Dickey–Fuller test, PACF tests, etc.
I found a wikipedia page of common statistical tests, but I am looking for a list of such that is specific f... |
I was reading this wikipedia article related to kriging . I didn't understand the part when it says that
Kriging computes the best linear unbiased estimator, $\hat Z (x_0)$, of $Z(x_0)$ such that kriging variance of is minimized with the unbiasedness condition. I didn't get the derivation and also how the variance is ... |
I am confused how gaussian processes and kriging are related? Can anyone please give me some simple explanation. I tried to go through the wiki but I didn't get it
|
I wanted to know what the n.minobsinnode parameter means in the GBM package. I read the manual, but it is not clear what it does.
Should that number be small or large to improve the results?
|
Suppose I observe i.i.d. $x_i \sim \mathcal{N}\left(\mu,\Sigma\right)$, and wish to test $H_0: A\ $vech$\left(\Sigma^{-1}\right) = a$ for a conformable matrix $A$ and vector $a$. Is there known work on this problem?
The obvious (to me) attempt would be via a likelihood ratio test, but it seems like maximizing the like... |
I'm trying to test various functional data analysis approaches.
Ideally, i'd like to test the panel of approaches i have on simulated functional data. I've tried to generate simulated FD using an approach based on a summing Gaussian noises (code below), but the resulting curves look much too rugged compared to the rea... |
Apology if this is too simple. I couldn't get the more advanced r-help group to respond.
I am planning to characterize workloads by measuring the correlation coefficient of two sets of real values but before that I wish to generate two sets of sample values that have a high coefficient and a low coefficient. I want to ... |
Say I have a project (you know the typical one you can represent using a Gantt Chart )
If I where to assign a particula probability to each of the tasks in the Gantt... say for example:
Task1 (2 days, i am 75% sure of that)
Task2 (4 days, i am 50% sure of that) for it to start, Task 1 most be finished
Task3 (8 days,... |
The Wikipedia article on the Gamma distribution,
lists two different parameterisation methods, one of them frequently used in Bayesian econometrics with $\alpha>0$ and $\beta>0$, $\alpha$ is shape parameter, $\beta$ is rate parameter.
$$X\sim \mathrm{Gamma}(\alpha,\beta).$$
In a Bayesian econometrics textbook written b... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.