instruction stringlengths 9 38.7k |
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for the following 3 values 222,1122,45444
WolframAlpha gives 0.706
Excel, using =SKEW(222,1122,45444) gives 1.729
What explains the difference?
|
I would like to plot the attached
as an area chart:
As you can see, personal income is divided into 26 intervals of varying width. I also have the average and mean income in the intervals.
To convey a truthful area graphic of this data, I wonder what my options really are?
Plotting the ordinal categorical data at hand... |
I have finally been able to wrap my head around the mechanics of how to initialize and train a multivariate Gaussian mixture model using expectation maximization algorithm. So I wonder how difficult this GMM and EM task is in comparison to all other common algorithms and models in machine learning. I appreciate any fee... |
I am assuming R has this built-in. How do I reference it?
|
First off, be warned: I am a complete stats novice. I'd like to learn, but at the moment I have an intense business problem to solve that I think (hope?) is straightforward enough that it could be answered easily. I will try to explain as simply as I can so I don't muck it up.
In short, i'm trying to find the right way... |
I've seen couple of articles reporting individuals standard deviations and/or standard errors for groups even after implementing ANOVA. My understanding is that groups SE's should be based on experimental error mean square. Any comment?
|
In S-plus estimates of percentiles for a survival function can be obtained using the qkaplanMeier function (on the results of a call to kaplanMeier) like that:
kfit <-kaplanMeier(censor(TIME,STATUS)~1)
qkaplanMeier(kfit, c(.25, .5, .75))
How can I do this in R?. Those functions do not exist anymore. What if I also wan... |
Where can I obtain all hourly weather data available?
Notes:
Ideally, this would include the history of all data currently published at:
here
here
here
I've obtained 10 years of METAR data from wunderground.com like this:
curl -H 'Cookie: Prefs=|SHOWMETAR:1|;' -o data.txt 'http://www.wunderground.com/history/air... |
I am currently looking for some Information Retrieval techniques.
I have a SQL database table containing strings. It has 1000 records, each being a random sentence I picked from random web sites. I need to get the term frequency and represent each string into a vector. I also need to cluster the records, e.g. using k-m... |
Let's take the following example:
set.seed(342)
x1 <- runif(100)
x2 <- runif(100)
y <- x1+x2 + 2*x1*x2 + rnorm(100)
fit <- lm(y~x1*x2)
This creates a model of y based on x1 and x2, using a OLS regression. If we wish to predict y for a given x_vec we could simply use the formula we get from the summary(fit).
However, ... |
We are trying to predict values of variable A having N other variables. What we do, we calculate Pearson correlation between A and each of the other N variables, for last M values, using fixed M. We use variable with largest correlation coefficient as predictor.
This scheme works fine when analyzing N variables during ... |
Given two point sets, $B$ consisting of blue points, and $R$ of red points, on the plane.
The problem is to formulate a theoretical model to compare the average runtime of the Computational Geometric (CG) Algorithm and the Perceptron Learning (PL) for shattering two sets of points by a line. ( Briefly, CG tests if th... |
Say there are 3 companies A, B and C. Each company has a quality rating from 0 to 100 and a price in USD.
Company Quality Price
A 80 7.9
B 70 8.0
C 75 8.1
How do I determine the best quality-price trade-off? What kind of analysis should I use?
|
I have heard of survival analysis and life data analysis, but don't quite get the big picture.
I was wondering what topics they are covering?
Is it pure statistics, or just application of statistics on some specific area?
Is life date analysis part of survival analysis?
Thanks and regards!
|
I am looking around for datasets mainly in the form of natural language text corpus, that has been redacted by experts. So far I found only the enron dataset, but it appears only a few specific things (like employee mail-id, etc.) were redacted, which will not be beneficial for feature extraction.
Something like decla... |
I would like to clarify how the Granger causality can/should be used in practice, and how to interpret the statistical significance given by the test.
Also, I would like to fill this table with things like "we don't know" or if we know something, what do we know (It will for sure not be causality, but maybe something e... |
I would like to propose a single model (decision tree), that is very variable, and validate it. I have choosen parameters after I had obtained good quality measures with a cross-validation.
I could build the model on the whole data set and show cross-validated measures. But I can't get a special graph (called Reliabili... |
While reading a few papers, I came across the term "gold set" or "gold standard". What I don't understand is what makes a dataset gold standard? Peer acceptance, citation count and if its the liberty of the researcher and the relevance to problem he is attacking?
|
I have a survival cancer clinical trials dataset from which I have generated Cox models using forward likelihood ratio testing within R. These models are based on 'traditional' cancer variables (eg. age, histology, metastasis etc).
I would like to extend the model using high dimensional data (where we have measured ma... |
I'm brand new to this R thing but am unsure which model to select.
I did a stepwise forward regression selecting each variable based on the lowest AIC. I came up with 3 models that I'm unsure which is the "best".
Model 1: Var1 (p=0.03) AIC=14.978
Model 2: Var1 (p=0.09) + Var2 (p=0.199) AIC = 12.543
Model 3: Var1 (p=0.... |
When you make the normal probability plot, the plot may have curved bounds. Then the plot should be roughly linear and the data must lie within the bounds provided by software. In the examples I have seen the normal was rejected because some data points were not within the bounds. Can you provide an example where the ... |
I have multiple variables (here: weight, horizontal diameter, price and dummy) related to different factors (here: Apple, Orange, Banana and Avocado):
Fruit Weight HorDiam Price Dummy
Apple 60 60 5 4
Apple 50 70 8 6
Orange 80 75 7 2
Orange 72 7... |
I have to build a multi-user web app which is about traffic measurements, prognoses etc. At this point I know that I'll use bar and pie charts.
Unfortunately, those chart types aren't rich in expressing all the data that I collect and compute.
I'm looking for a collection of graphical charts. It is very ok if I have ... |
I'm doing some Machine Learning in R using the nnet package. I want to estimate the generalisation performance of my classifier by using k-fold cross-validation.
How should I go about doing this? Are there some built-in functions that do this for me? I've seen tune.nnet() in the e1071 package, but I'm not sure that doe... |
Seasonal adjustment is a crucial step preprocessing the data for further research. Researcher however has a number of options for trend-cycle-seasonal decomposition. The most common (judging by the number of citations in empirical literature) rival seasonal decomposition methods are X-11(12)-ARIMA, Tramo/Seats (both im... |
I wrote a script tests the data using the wilcox.test, but when I got the results, all the p-values where equal to 1.
I read in some websites that you could use jitter before testing the data (to avoid ties as they said), I did this and now I have an acceptable result.
Is it wrong to do this?
test<- function(column,da... |
I am about to try out a BUGS style environment for estimating Bayesian models. Are there any important advantages to consider in choosing between OpenBugs or JAGS? Is one likely to replace the other in the foreseeable future?
I will be using the chosen Gibbs Sampler with R. I don't have a specific application yet,... |
I have a distribution $X$. By playing around with random samples from $X$, I've determined that $Var(X^i) > Var(X)$ where $i > 1$. However, I can't seem to find a formula for the expected variance of $X^i$, or why it should be greater than $Var(X)$.
Moving away from normal distributions, should it generalize that the s... |
I was wondering how statistics and decision theory are related?
It looks to me all the statistics problems/tasks can be formulated in decision theory. Also problems in decision theory can be formulated in statistics/probability problems, or in deterministic way. So is statistics just a part of the problems studied in ... |
Previosuly I have asked how to compute some conditional probabilities, but I am missing this particular case:
lets say we now have 3 variables:
$T$, $L$, $E$:
T L
\ /
E
So
$E$ depends on $T$ and $E$ depends on $L$
I have these probabilities:
$P(T) =$ 0.0104
$P(L) =$ 0.055
$P(E) =$ 0.0648
$P(E|L,T) =... |
Latent semantic indexing seems to work well; e.g. it is independent of language, etc.
However, it appears to use the similarity of frequencies of terms in the corpus to categorize them.
If this understanding is correct, is there a way to measure the size of the dataset that will give optimal performance?
|
Data Mining and Statistical Analysis has a general discussion on stats vs data mining. If I may, narrow down the question a bit - are there any general demarcations that allows you to decide which approach is more suited for using - LDA or ARM? (other than appreciation for the maths in the former)
|
I plan to conduct a research study about Interaction Designers.
Prior to starting on sampling methods I am finding it very hard to get my hands on some demographics and statistics, e.g. How many people are registered to be employed as Interaction Designers, User Experience Designers etc. in a particular territory (UK ... |
str(test)
'data.frame': 767 obs. of 2 variables:
$ datefield: Ord.factor w/ 59 levels "1984-04-01"<"1984-07-01"<..: 1 2 3 4 5 6 7 8 9 10
$ somevar : num 43.7 55.6 43.5 54.1 42.8 ...
> str(Italy)
'data.frame': 1008 obs. of 2 variables:
$ year: Ord.factor w/ 48 levels "1951"<"1952"<..: 1 1 1 1 1 1 1 1 1 1 ... |
Assume you are given two objects whose exact locations are unknown, but are distributed according to normal distributions with known parameters (e.g. $a \sim N(m, s)$ and $b \sim N(v, t))$. We can assume these are both bivariate normals, such that the positions are described by a distribution over $(x,y)$ coordinates (... |
What does it mean for a study to be over-powered?
My impression is that it means that your sample sizes are so large that you have the power to detect minuscule effect sizes. These effect sizes are perhaps so small that they are more likely to result from slight biases in the sampling process than a (not necessarily ... |
In SVM (linear kernel) classification analyses of a data-set of gene expression (~400 variables/genes) for ~25 each of cases and controls, I find that the gene expression-based classifiers have very good performance characteristics. The cases and controls do not differ significantly for a number of categorical and cont... |
Here is some context. I am interested in determining how two environmental variables (temperature, nutrient levels) impact the mean value of a response variable over a 11 year period. Within each year, there is data from over 100k locations.
The goal is to determine whether, over the 11 year period, the mean value of t... |
I have several dependent variables that are measures of racial disproportionality; I've calculated them as:
% of events caused by racial minority group / % of events caused by racial majority group
I have a dependent variable for each racial minority group in my sample. I am running longitudinal Generalized Estimating ... |
There is a web service where I can request information about a random item.
For every request each item has an equal chance of being returned.
I can keep requesting items and record the number of duplicates and unique. How can I use this data to estimate the total number of items?
|
What does it mean if the F value in one-way ANOVA is less than 1?
Remember the F-ratio is
$$\frac{\sigma^2+\frac{r\times\sum_{i=1}^t \tau_i^2}{t-1}}{\sigma^2}$$
|
For the $\nu$-SVM (for both classification and regression cases) the $\nu \in (0;1)$ should be selected.
The LIBSVM guide suggests to use grid search for identifying the optimal value of the $C$ parameter for $C$-SVM, it also recommends to try following values $C = 2^{-5}, 2^{-3}, \dots, 2^{15}$.
So the question is, ar... |
I am running a GAM-based regression using the R package gamlss and assuming a zero-inflated beta distribution of the data. I have only a single explanatory variable in my model, so it's basically: mymodel = gamlss(response ~ input, family=BEZI).
The algorithm gives me the coefficient $k$ for the impact of the explanat... |
Recent history suggests that one supplier fails to meet this new specification 20% of the time. Assume that the next 15 batches of this alloy are a random sample.
How can I find the expected number of shipments that do meet the new specifications,
and the standard deviation?
|
I am using SPSS and having some trouble with a research question which is analogous to the hypothetical question:
Is there a longitudinal Relationship between Happiness and Chocolate Consumption?
Let’s say I take a sample of people and contact them when they are aged 14 and aged 18 and ask them:
a) What is your choco... |
Given a collections of sets, which have an inherent but unknown (at runtime) hierarchy, I would like to cluster them based on the sub/super-relationships with respect to their elements. Let me try and illustrate this with a overly simplified example:
Set 1 = {a, b, c, d, e, f}
Set 2 = {a, b}
Set 3 = {a, b, c ,d}
Set 4... |
I'm in the process of running a repeated-measures ANOVA on two groups of participants from an experiment. In one group, there are 10 participants, and in the other group, there is only 1 participant. This is because the 1 participant is a patient who is being compared to the 10 other participants.
Now, my question is: ... |
I can't seem to do a comparison with a sum of numbers and get the right answer (lines alternate between my input and R output):
(.6 + .3 + .1) == 1
[1] FALSE
(.6 + .3 + .1)
[1] 1
1
[1] 1
I've tried with and without parenthesis, tried comparing to 1.0, tried using as.numeric, but can't get it to work.
|
I'm concerned about treating my data as gold, especially in areas of low data support, so I would like to apply additive smoothing. I'm then doing several things with this data, and one of them is Pearson's chi-square test for independence. Is it still acceptable to first do the smoothing and then do the chi-square t... |
Background
I am designing a Monte Carlo simulation that combines the outputs of series of models, and I want to be sure that the simulation will allow me to make reasonable claims about the probability of the simulated outcome and the precision of that probability estimate.
The simulation will find the probability that... |
I'm trying to use the nnet library in R, and can't seem to work out how to use the reltol parameter. It says in the docs:
Stop if the optimizer is unable to reduce the fit criterion by a factor of at least 1 - reltol.
I assume this means that if reltol = 0.5 then it will stop if it can't halve the error rate, and if ... |
Very basic question, I suspect. It's sort of the inverse of this one, and the same disclaimers about my own ignorance apply, but here goes:
I have a sampling technology. I know the total population, and I know the number of samples I've done. What's the best way to calculate and express how confident I am that my resul... |
I have a spatial error model that I have estimated and would like to create a figure with the prediction interval. By spatial error model, I mean that the errors are spatially correlated and thus OLS is unbiased but inefficient (not a spatially auto-regressive model).
I used the geostatistical approach to spatial stati... |
Hope this newbie question is the right question for this site:
Suppose I would like to compare the composition of ecological communities at two sites A, B. I know all three sites have dogs, cats, cows, and birds, so I sample their abundances at each site (I don't really have an "expected" abundance for each animal at e... |
Could you recommend an easy to use or comprehensive conjoint analysis package for R?
|
What is a good book that covers mixed distributions?
Most statistics books either only briefly mention them or do not cover the topic at all.
I'd like to have a comprehensive resource covering issues of joint distributions with both discrete and continuous variables, conditional and marginal distributions in the mixe... |
This is a more "statistical" version of my Math.SE problem .
Question Let $\mathbf{P}$ be a convex polygon of $m$ sides. Pick two of its edges at random, and further pick a random point on each of these edges, and compute the length of the chord we get. If we repeat this process $n$ times,and average the chord leng... |
a journal article has a method for designing experiments to be fit to a 4-parameter logistic model. The model used is $y= D + \frac{A - D}{1 + (\frac{x}{C}) ^ B}$
A = upper asymptote
B = maximum slope
C = x value when y = 50% of maximum (i.e. 1/2 of upper asymptote)
D = lower asymptote
Using pilot data, further experi... |
I'm given an $n\times n$ grid of positive integer values. These numbers represent an intensity that should correspond to the strength of belief of a person occupying that grid location (a higher value indicating a higher belief). A person will in general have an influence over multiple grid cells.
I believe that the p... |
REF: http://en.wikipedia.org/wiki/Order_of_integration
What is the interpretation/intuition behind a time series integrable of order 0? I am reading something on cointegration and this is not yet clear to me.
|
A colleague just asked me this question:
Context:
A psychological study had
2 groups of participants (between subjects)
4 contexts (within subjects))
each participant provided a response in each of the four contexts
there were three categorically distinct response options (lets call them $A$, $B$, and $C$)
Question
... |
Consider a conjugate prior in the k-parameter canonical exponential family:
$$p(w|n_0,y_0)=c(n_0,y_0) \exp(n_0(y_0 w'-b(w))) \, ,$$
where $n_0>0, y_0 \in Y$ is the pseudo observation vector, and $Y$ is an open subset of $\mathbb{R}^k$.
I have to prove that the normalization constant $c(n_0,y_0)$ goes to zero when $y_0... |
I am using the evolfft function in the RSEIS R package to do a STFT analysis of a signal.
The signal is one hour long and it was acquired during 3 different conditions, in particular 0-20' control, 20'-40' stimulus, 40'-60' after stimulus.
Visually, I see a change in the spectrogram during these 3 periods, with higher ... |
What is a family of functions which goes from 0 to 1 and has one or more parameters that alters the rate at which a value of 1 is approached?
|
I can see that there are a lot of formal differences between Kullback–Leibler vs Kolmogorov-Smirnov distance measures.
However, both are used to measure the distance between distributions.
Is there a typical situation where one should be used instead of the other?
What is the rationale to do so?
|
SPSS returns lower and upper bounds for Reliability. While calculating the Standard Error of Measurement, should we use the Lower and Upper bounds or continue using the Reliability estimate.
I am using the formula :
$$\text{SEM}\% =\left(\text{SD}\times\sqrt{1-R_1} \times 1/\text{mean}\right) × 100$$
where SD is the s... |
Can you suggest a good review of case control matching algorithms? Algorithms that can be used to set up the matched pairs of one case and one control, or matched blocks of a case and multiple controls.(Preferably a paper, book chapter or website discussing recent developments.)
|
I have used LDA on a corpus of documents and found some topics. The output of my code is two matrices containing probabilities; one doc-topic probabilities and the other word-topic probabilities. But I actually don't know how to use these results to predict the topic of a new document. I am using Gibbs sampling. Does a... |
I was reading a Wikipedia article on the birthday paradox and stumbled upon the following statement:
...the pairings in a group of 23 people are not statistically equivalent to 253 pairs chosen independently...
Could you explain what does it mean and why does it matter in this case?
Here is the quotation in its orig... |
I am planning to write a program that performs MDS. Any pointers to where I can access the pseudo-code for MDS?
Thanks!
|
From Econometrics, by Fumio Hayashi (Chpt 1):
Unconditional Homoskedasticity:
The second moment of the error terms E(εᵢ²) is constant across the observations
The functional form E(εᵢ²|xi) is constant across the observations
Conditional Homoskedasticity:
The restriction that the second moment of the error terms E(εᵢ²... |
I'd love a check if anyone is willing!
I am trying to see if there is a statistical difference in female size between sites. Over the years females were repeatedly sampled within sites. I have sampled females opportunistically. Meaning that females were sampled a different number of times between and within sites.
My f... |
EDIT: Thanks for the help so far. I have updated the question based on further work.
I am interested in finding any difference in response of counts of two competing species to dryness and elevation. Both are caught in the same type of trap, but trap placement (bushes vs buildings) probably biases toward one species o... |
Say I've got a predictive classification model based on a random forest (using the randomForest package in R). I'd like to set it up so that end-users can specify an item to generate a prediction for, and it'll output a classification likelihood. So far, no problem.
But it would be useful/cool to be able to output some... |
We have a series of experiments where we measure virus transmission to plants when exposed to virus-infected insects for different time periods, so all of the experiments have similar types of independent and dependent variables. In one experiment, there are 6 time periods (1 to 24 hours) and 25 plants were tested (in... |
I am new to the use of cubic splines for regression purposes and wanted to find out
1) What is a good source (besides ESL which I read but am still uncertain) to learn about splines for regression?
2) How would you calculate the basis of a given natural cubic spline solution on new data? Specifically if one were to d... |
Context:
I have a series of figures for car sales that show me (a) the usual number of car sales for particular models and (b) the number of car sales by a particular car salesperson for each model.
Let's say the values are:
Model | Sales by all Salespeople | Sales by Salesperson x
A | 100 | ... |
Context:
From a question on Mathematics Stack Exchange (Can I build a program), someone has a set of $x-y$ points, and wants to fit a curve to it, linear, exponential or logarithmic.
The usual method is to start by choosing one of these (which specifies the model), and then do the statistical calculations.
But what is... |
I have a multiple linear regression problem $y=X\beta+\epsilon$. The number of observations $m$ is large, so by the time the data gets to me it's been summarized into:
$m$
$X^TX$
$X^Ty$
$y^Ty$
$\sum_{i=1}^m{y_i}$
The above list appears sufficient to compute the OLS estimate. But can it be used to compute a regularize... |
I am using hierarchical clustering to analyze time series data. My code is implemented using the Mathematica function DirectAgglomerate[...], which generates hierarchical clusters given the following inputs:
a distance matrix D
the name of the method used to determine inter-cluster linkage.
I have calculated the dist... |
I am looking at extremely non linear data for which the ARMA/ARIMA models do not work well. Though, I see some autocorrelation, and I suspect to have better results for non linear autocorrelation.
1/ is there an equivalent of the PACF for rank correlation? (in R?)
2/ is there an equivalent of ARMA model for non linear ... |
When doing multivariate regression, it's often the case that some predictors often have many zero values - dichotomous inputs, dummy coding of polychotomous inputs, interval coding, etc. The fraction of nonzero observations for a predictor is especially decreased when interacting these variables.
It seems obvious that... |
I'm playing with support vector machines (SVM) using the e1071::svm() function in R, and I encountered a scenario where I asked it for a leave-one-out cross-validated classification of a 2-category response and obtained a total accuracy of 38% (35/90), which, given 90 samples, ends up with a 95% confidence interval tha... |
The wonderful libsvm package provides a python interface and a file "easy.py" that automatically searches for learning parameters (cost & gamma) that maximize the accuracy of the classifier. Within a given candidate set of learning parameters, accuracy is operationalized by cross-validation, but I feel like this underm... |
When you are trying to fit models to a large dataset, the common advice is to partition the data into three parts: the training, validation, and test dataset.
This is because the models usually have three "levels" of parameters: the first "parameter" is the model class (e.g. SVM, neural network, random forest), the sec... |
I have four numeric variables. All of them are measures of soil quality. Higher the variable, higher the quality. The range for all of them is different:
Var1 from 1 to 10
Var2 from 1000 to 2000
Var3 from 150 to 300
Var4 from 0 to 5
I need to combine four variables into single soil quality score which will successfully... |
What are some good papers describing applications of statistics that would be fun and informative to read? Just to be clear, I'm not really looking for papers describing new statistical methods (e.g., a paper on least angle regression), but rather papers describing how to solve real-world problems.
For example, one pap... |
How would I go about finding out the confidence intervals around a set of distinct bianary occurrences where each occurence has a different associated probability and each occurence is weighted?
To be more specific, we typically determine a milestone budget by assigning reasonable probabilities to each milestone. Each... |
In the paper
M. Avellaneda and J. H. Lee, Statistical arbitrage in the U.S. equities market, July 2008,
in the Appendix on page 46, how does he get equilibrium standard deviation as following:
$$\sigma_{eq} = \sqrt{\frac{\text{Variance}(\zeta)}{1 − b^2}}$$
If anyone knows the paper, please explain.
Much appreciated,... |
I'm working with a CSV which contains approximately 220,000 entries. My aim is to predict one of the attributes (ATT1) using the other 3 (ATT2, ATT3, ATT4).
I've been able to do this using NaiveBayes, but now I feel unsatisfied with the result. The reason is that ATT1 can be one of 6 values (VAL1-6), but these are not ... |
I was wondering from the view of dividing the topics of statistical theory into inference part and non-inference part, what inference topics and non-inference topics statistical theory is covering?
By inference, I mean the task in logic to reach some conclusion from some premises. Probabilistic inference is a way of lo... |
I'm doing 10-fold cross validation on a dataset. But in some folds there are edge cases that the denominator in precision-recall calculation is zero (tp + fp =0).
What are the correct values for precision and recall in this case? And what is the correct way of doing cross-validation (should I include these results when... |
I am using the Holt-Winters' exponential smoothing technique to forecast expenditure data 2 years into the furture. The monthly data has an increasing trend and annual seasonality.
I'm using MS Excel with the Solver add-in to calculate the optimal values of $\alpha$, $\beta$ and $\gamma$ to give the smallest MSE for th... |
An English soccer team plays a series of matches against different opponents of varying ability. A bookmaker offers odds for each match as to whether it will be a home win, away win, or draw. Part-way through the season, the team has played $n$ matches and has drawn $k$ of them, which is more than might be expected fro... |
My data looks like this (F=Features)
F1 F2 F3 F4 F5 F6 F7 F8....
ID1 0.67 0.76 0.3 0.54 0.21 0.88 0.97 0.45....
ID2 0.76 0.68 0.10 0.45 0.12 0.44 0.79 0.54....
ID3 0.67 0.76 0.3 0.54 0.21 0.88 0.68 0.76....
ID4 0.67 0.10 ... |
I don't know what is the appropriate term for my question. The scenario is described as following.
In the analysis there one dependent variable Y and two independent variable X1 and X2.
All three variables are continuous.
I converted X1 into a categorical variable which has three levels A, B, and C. It was found that Y... |
In the paper
M. Avellaneda and J. H. Lee, Statistical arbitrage in the U.S. equities market, July 2008,
in the Appendix on page 44, I have some questions.
First he runs the regression of stock-return ($R_n^S$) with index/ETF-return ($R_n^I$).
$R_n^S = \beta_0 + \beta R_n^I + \epsilon_n, ~~~~~n=1,2,...,60$
Then he d... |
Suppose you get to observe "matches" between buyers and sellers in a market. You also get to observe characteristics of both buyers and sellers which you would like to use to predict future matches & make recommendations to both sides of the market.
For simplicity, assume there are N buyers and N sellers and that e... |
My actual project is a bit complicated, but I'll explain by analogy (which I hope facilitates response):
I have 3 substances, say water, motor oil, and ethanol. For each substance, I have 5 samples in a beaker (total 15 beakers). I heat all the beakers on a hot-plate up to 70 degrees Celsius, and over the next hour, I ... |
I have two random poisson variables $x_1$ and $x_2$ with value 10 and 25 respectively. I am interested to use likelihood ratio test to test the null hypothesis: $\lambda_1=\lambda_2$, versus alernate hypthesis $\lambda_1$ not equal to $\lambda_2$.
I want to use simulation to calculate power and alpha values. I would wa... |
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