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What is the worst classier that learns badly in practical problems?
Edit:
Especially bad on test data..
Thanks
|
I apologize in advance for the vague title, but I couldn't think of anything better.
I have two datasets, where one is a very small subset of the other. The percentage of people who have a specific attribute in the large dataset is x%. The percentage of people who have the same attribute in the subset is y%. The subset... |
I'm a beginner to statistics (taken only one college course), but I have a background in programming.
I just started playing with a Bayesian classifier library for Ruby and I am looking for ideas for things to analyze.
Right now I'm messing around with Tweet categorization, but do you have any ideas?
More importantly,... |
I am slightly new to writing functions in R.
Here I have a basic function that searches for a pattern and returns the indexes of where the occurence occurs given a list dataset
#this functions takes a pattern and prints the indexes for the matches
find_domain <- function(pattern,list) grep(pattern,list,ignore.case=T)
... |
I am trying to do Bayesian posterior predictive checking, whereby I calculate the DIC for my fitted model, and compare to DIC from data simulated from the fitted model. I can get the DIC out of winBUGS, however I am not sure how to calculate the likelihood (for the DIC) outside of winBUGS (i.e., without fitting new mod... |
I have a python script that creates a list of lists of server uptime and performance data, where each sub-list (or 'row') contains a particular cluster's stats. For example, nicely formatted it looks something like this:
------- ------------- ------------ ---------- -------------------
Cluster %Availability Requ... |
I'm a programmer with little statistical background, and I'm trying to create something similar to what facebook did recently (with other data):
http://www.facebook.com/notes/facebook-data-team/whats-on-your-mind/477517358858
That is to be able to find correlation between one variable (age) and bunch of other variables... |
THis is a data visualization question. I have a database that contains some data that is constantly revised (online update).
What is the best way in R to update a graph every let say 5 or 10 seconds. (without plotting again the all thing is possible)?
fRed
|
What methods can I use to infer a distribution if I know only three percentiles?
For example, I know that in a certain data set, the fifth percentile is 8,135, the 50th percentile is 11,259, and the 95th percentile is 23,611. I want to be able to go from any other number to its percentile.
It's not my data, and those... |
Given observations of $\{y, x_1, x_2, \cdots, x_n\}$, we can always do a linear regression and get all the coefficients $\{c_i\}$ for the model
$$y = c_0 + c_1 x_1 + \cdots + c_n x_n.$$
However, this may not be the best answer. Let me explain it.
When we are doing a regression, we have estimates $\{d_i\}$ for the stand... |
I'm a medical student trying to understand statistics(!) - so please be gentle! ;)
I'm writing an essay containing a fair amount of statistical analysis including survival analysis (Kaplan-Meier, Log-Rank and Cox regression).
I ran a Cox regression on my data trying to find out if I can find a significant difference be... |
I came across a picture of an application prototype that finds significant changes ("trends" - not spikes/outliers) in traffic data:
I want to write a program (Java, optionally R) that is able to do the same - but because my statistic skills are a little rusty, I need to dig into this topic again.
What approach/algori... |
I am just learning PCA and wondering if it is just a more sophisticated form of sampling. In other words if I have a large data set and take a random sample, would I then apply PCA to it? Or just apply PCA to the data set?
|
(I'm asking this question for a friend, honest...)
Is there an easy way to convert from
an SPSS file to a SAS file, which
preserves the formats AND labels?
Saving as a POR file gets me the
labels (I think) but not the POR file.
I tried to save to a SAS7dat file but
it didn't work. Thanks,
|
As the title says, I'd like to calculate the percentage difference for two sets of points. For example, suppose I have $S_{1}=\{(1,x_{1}),(2,x_{2}),(3,x_{3})\}$ and $S_{2}=\{(1,y_{1}),(2,y_{2}),(3,y_{3})\}$. How can I know the difference in percentage between both sets of data. What is the correct way to do that? Is th... |
I have animals, that could be virgin or mated (reproductive state is the fixed factor), which I've stimulated sequentially with 4 different doses of an odour (doses are the repeated measures, the same animal was blown with 4 increasing doses of the same odorant). Then, I measure the neuronal response (variable: number ... |
Obviously events A and B are independent iff Pr$(A\cap B)$ = Pr$(A)$Pr$(B)$. Let's define a related quantity Q:
$Q\equiv\frac{\mathrm{Pr}(A\cap B)}{\mathrm{Pr}(A)\mathrm{Pr}(B)}$
So A and B are independent iff Q = 1 (assuming the denominator is nonzero). Does Q actually have a name though? I feel like it refers to s... |
I'm doing a simple AIC-based backward elimination model where some variables are categorical variables with multiple levels. These variables are modeled as a set of dummy variables. When doing backward elimination, should I be removing all the levels of a variable together? Or should I treat each dummy variable separat... |
I try to install rpy2 in my system,
(I compile R with --enable-R-shlib and with --enable-BLAS-shlib flags)
but when I try in python console
import rpy2
import rpy2.robjects
I got:
Traceback (most recent call last):
File "<stdin>", line 1, in<module>
File "/usr/lib/python2.6/dist-packages/rpy2/robjects/__init__... |
I have been running 3-level multilevel models with HLM, and my main interest is in some cross-level interaction effects that I am finding. My concern is that the effect sizes of these interactions appear to be small – I am wondering whether they are really meaningful.
I am turning to you to ask whether anyone could adv... |
I have carried out a stepwise logistic regression in JMP. Then (using the proper button in the program window), I have chosen to build a nominal logistic regression model using (only) the variables identified by the stepwise procedure.
Anyhow, comparing the summary tables of the stepwise regression and the nominal one,... |
Okay, so I think I have a decent enough sample, taking into account the 20:1 rule of thumb: a fairly large sample (N=374) for a total of 7 candidate predictor variables.
My problem is the following: whatever set of predictor variables I use, the classifications never get better than a specificity of 100% and a sensiti... |
I'm not sure if this is precisely a measurement error model or not. I'm working on performing meta analysis, and the model I'm starting with is fairly basic.
\begin{aligned}
X_i &= \mu_i + e_i \\
Y_i &= \beta \mu_i + g_i + \delta_i
\end{aligned}
The random components are $e_i$, $g_i$, and $\delta_i$,and the variance i... |
Context: I am a programmer with some (half-forgotten) experience in statistics from uni courses. Recently I stumbled upon http://akinator.com and spent some time trying to make it fail. And who wasn't? :)
I've decided to find out how it could work. After googling and reading related blog posts and adding some of my (li... |
I'm a statistics newbie (medical student) trying my luck with a Cox regression for a survival analysis on the outcome of a specific type of operation. And I'm trying to determine which variables to control for. And how to handle the age of the patient at operation-time (measure-start)...
Currently I've set the followin... |
Another newbie question here (probably piece of cake for you guys).
When I run a Cox Regression and one of my covariates come out as significant:
95,0% CI for Exp(B)
B SE Wald df Sig. Exp(B) Lower Upper
risk 2,224 1,107 4,036 1 ... |
I want to do a chi-squared test on data that looks like this:
A B
0 0
1 0
0 1
1 1
8 0
3 4
...
You can think of each pair as one trial with two participants. In each trial, there are a different number of observations for each participant.
I have binned each data pair like so: I counted how many pairs have 0 for both ... |
I did a linear regression in R and got the following result:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 192116.40 6437.27 29.844 < 2e-16 ***
cdd 272.74 26.94 10.123 1.56e-09 ***
pmax(hdd - 450, 0) 61.73 22.54 2.738 0.0123 *
---
Signif.... |
I'm trying to fit the GAMLSS library's Sichel distribution to some zero-truncated data, but the only way to get the function to work is to include the zero-class anyway but give it a frequency of 0, which doesn't take into account the zero-truncated nature of my data. Can anyone suggest a way to properly "redistribute"... |
So assuming that there is a point in testing the normality assumption for anova (see 1 and 2)
How can it be tested in R?
I would expect to do something like:
## From Venables and Ripley (2002) p.165.
utils::data(npk, package="MASS")
npk.aovE <- aov(yield ~ N*P*K + Error(block), npk)
residuals(npk.aovE)
qqnorm(residual... |
I have a bunch of data like this:
P1 [1, 2, 3, 4, 5, 6, 7, 8, 10]
P2 [5, 8, 10, 12, 20]
P3 [10, 201, 440]
P4 [1, 2, 10]
P5 [1, 2]
Right now it's ranked by the size of its data set (as shown above), so values that are heavily represented on the chart are on top e.g., P1 has the most)
I'm trying to rank this data so tha... |
Possible Duplicate:
What book would you recommend for non-statisticians?
Hello all,
Which is a good book for self-learning of statistics? I tried the "Head first statistics" which starts very well, but when talking on t-distribution and some more complex issues, its quality degrades (just my opinion). Also, smth li... |
I'm working on benchmarking the speed of various JavaScript methods.
Part of the benchmark process requires repeating a test for a minimum time (to reduce the percentage uncertainty to at or less than 1%). There is some overhead on each test (the cost of the loop, incrementing a counter variable and so on). I currently... |
Say I have a process that gives me 3 outputs: $O^1$, $O^2$ and $O^3$.
The outputs are generated from a semi-deterministic process, i.e. there is a deterministic component in the outputs, along with a random component.
In particular, having $n$ measurements over time, the outputs $O_j \quad j=1,2,...,n$ are -at least in... |
I have a real-life situation that can be solved using Queueing Theory.
This should be easy for someone in the field. Any pointers would be appreciated.
Scenario:
There is a single Queue and N Servers.
When a server becomes free, the Task at the front of the queue gets serviced.
The mean service time is T seconds.
The ... |
I'm currently applying the Roy Zelner test of poolability as shown
in the excellent article of Andrea Vaona,
in fact I'm working with panel N=17 T=5, and my model looks like
this :
$$Y_{it}= a_0+B_1X_1+B_2X_2+B_3X_3+B_4X_4+e_{it}$$
My question is the following. When I'm testing for coefficient equality of the unp... |
I start with three independent random variables, $X_1, X_2, X_3$. They are each normally distributed with:
$$X_i \sim N(\mu_i, \sigma^2), i = 1, 2, 3.$$
I then have three transformations,
$$\eqalign{
Y_1 &= -X_1/\sqrt{2} + X_2/\sqrt{2} \cr
Y_2 &= -X_1/\sqrt{3} - X_2/\sqrt{3} + X_3/\sqrt{3} \cr
Y_3 &= X_1/\sqrt{... |
Suppose I have a biased coin (heads with probability p), and I keep flipping it until I get t tails. So I had to flip n times in total to get t tails. How do I find a (frequentist) confidence interval for the probability of heads p?
|
This is a softmax probability distribution:
$$P(i| w_1, w_2, \ldots, w_n) = \frac{exp(w_i)}{\sum_{i=1}^n exp(w_i)}.$$
It known also as Boltzmann distribution. It is used in generalized Bradley-Terry model and in multinomial logistic regression. There are efficient minorization-maximization algorithms for infering $\vec... |
Here is the problem: A survey contains 7 binary questions (Yes/No responses). If two people are answering the survey, what is the probability for their answers on 4 or more of the questions to match? In other words, if we have four or more matching answers, we can consider the overall survey response to be similar for ... |
I'm analyzing people based on their twitter stream. We are using a 'word bag' model of users, which basically amounts to counting how often each word appears in a persons twitter stream (and then using that as a proxy for a more normalized 'probability they will use a given word' in a particular length of text).
Due t... |
I have almost two questions. I need a single covariate logistic regression (LR) for each of my variables. Should I do it manually in SPSS, selecting each variable and do logistic regression? Is there a "for each" cycle to do it? I should switch to R language to have what I want.
In the multivariables (multi covariates... |
I have a sample survey of a population whose distributions of certain characteristics are not identical to the distributions of the overall population. For example, the age of my respondents may be biased downward, or the incomes in my sample may be too high compared to the population (or my theoretical population dis... |
I have data from an experiment that I analyzed using t-tests. The dependent variable is interval scaled and the data are either unpaired (i.e., 2 groups) or paired (i.e., within-subjects).
E.g. (within subjects):
x1 <- c(99, 99.5, 65, 100, 99, 99.5, 99, 99.5, 99.5, 57, 100, 99.5,
99.5, 99, 99, 99.5, 89.5, 99.... |
I think people here could guide me in solving a problem related to anomaly detection in Computer Science. The term anomaly here refers to some undesired event occuring in the system like a virus infection.
I could get to know about it from more than one source. For example, after having extracted a value from two diffe... |
I'm studying Biomedical Computer science and I have to research a paper about genotype-phenotype association.
In this paper the authors use a correlation analysis by first calculating the Pearson correlation and then calculating the hypergeometric distribution to filter out insignificant associations.
http://www.biomed... |
I am now writing my bachelors thesis and I have come across some difficulties. I am about to do some panel regressions with time and entity fixed effects and I would therefore like to use the plm package. But when I do add fixed effects and want to have heteroscedasticity robust standard errors they seem to be incorrec... |
I tried to group a set of elements and to calculate the row means
If my list has more than one element, it works fine:
tapply(colnames(myMA), c(1,1,1,2,2,2,3,3,4,4), list)
myMAmean <- sapply(myList, function(x) rowMeans(myMA[,x]))
However, in my data some of the rows are unique:
myList <- tapply(colnames(myMA), c(... |
I want to find the conjugate prior distribution for the Fisher's noncentral hypergeometric distribution? Basically I want to integrate the parameters out of the distributions to arrive at the Bayesian Likelihood of observing some data with the noncentral hypergeometric distribution.
|
Problem
I would like to plot the variance explained by each of 30 parameters, for example as a barplot with a different bar for each parameter, and variance on the y axis:
However, the variances are are strongly skewed toward small values, including 0, as can be seen in the histogram below:
If I transform them by $\l... |
I want to test if there is a rivalry among two siblings in a family. I have 15 questions in my study and I let my 100 respondents ( distributed equally to two siblings) ranked them 1 to 15.
How should I analyse this data?
|
I have a (I suspect) simple question. I have time series cross section data on voting behaviour in the Council of the European Union (the monthly number of yes, no and abstentions for each member state from 1999 to 2007). So basically the variables are counts, thus a Poisson/negative binomial regression would be approp... |
Anyone know why when you run a SEM model in SAS using proc calis (or tcalis) you do not get p-values for the parameter estimates? It does supply a t-value however.
Two popular SEM packages in R, 'sem' and 'lavaan', both give p-values for the estimates but they use a Z test statistic.
|
I am not sure the subject enters into the CrossValidated interest. You'll tell me.
I have to study a graph (from the graph theory)
ie.
I have a certain number of dots that are connected.
I have a table with all the dots and the dots each one is dependant on.
(I have also another table with the implications)
My questio... |
I collected some data with an instruments with 1Hz sampling clock, now I want to low-pass filter the data to separate the mean and fluctuation part (Reynolds decomposition).
How can I design a low-pass filter with a cutoff period of 20 minutes?
|
Deming Regression is a regression technique taking into account uncertainty in both the explanatory and dependent variable.
Although I have found some interesting references on the calculation of this property in matlab and in R I'm stuck when I try to calculate the standard prediction error. The error on the model est... |
I have large comparison data in form
In a pairwise comparison data each data point compares two alternatives.
For instance:
A > B (A is preferred to B, A and B are classes, not numbers)
A > B
B > A
B > C
A > C
etc ...
In short we can write numbers of preferences in data set:
A vs B 999:1
X vs A 500:500
X vs B 500:50... |
What are the appropriate uses for a grouped vs a stacked bar plot?
|
I am trying to model future sales data for products which have very low sales volume. I am a programmer with a smattering in statistics, so I apologise in advance if this qustion is naive!
My question is what distribution is most suitable for my sales profile and is it possible to verify the distribution. The exact f... |
I'm interested in learning more about nonparametric Bayesian (and related) techniques. My background is in computer science and though I have never taken a course on measure theory or probability theory, I have had a limited amount of formal training in probability and statistics. Can anyone recommend a readable introd... |
Confidence intervals for binomial proportions have irregular coverage over the range of possible population parameters (e.g. see Brown et al. 2001 <Link>). How can I formally and usefully describe the properties of the confidence intervals?
Say I toss a coin ten times and obtain seven heads. Are the following statement... |
I am using IDL regression function to compute the multiple linear correlation coefficient...
x = [transpose(anom1),transpose(anom2),transpose(anom3)]
coef = regress(x,y, const=a0, correlation=corr, mcorrelation=mcorr, sigma=stderr)
mcorr is returned with values between 0.0 and 1.0. Clearly, the result of the following... |
I've never taken a stats course so I really don't know where to begin on this.
I am using microcontroller that according to the datasheet, has a Flash memory that can be reprogrammed a minimum of 10,000 times, with 100,000 times being a more typical number.
These numbers seem low to me (based on other devices using a s... |
Still learning basic functions in R,
The subset function seems to only filter based a condition based on single column with or without multiple conditions?
How can I easily filter data from a dataframe?
when you are provided with multiple conditions
When the condition needs to be applied across the available columns.
... |
I have daily measurements of nitrogen dioxide for one year (365 days) and the interquartile (IQR) is 24 microgram per cubic meter. What does "24" mean in this context, apart from the definition of IQR which is the difference between the 25th and 75th percentile? How would you explain this figure to a journalist, for ex... |
Cross-posted at Math.SE.
I'm working on a hobby project and would need some help with the following problem.
A bit of context
Let's say there is a collection of items with a description of features and a price. Imagine a list of cars and prices. All cars have a list of features, e.g. engine size, color, horse power, mo... |
I made a logistic regression model using glm in R. I have two independent variables. How can I plot the decision boundary of my model in the scatter plot of the two variables. For example, how can I plot a figure like here.
|
I developed the ez package for R as a means to help folks transition from stats packages like SPSS to R. This is (hopefully) achieved by simplifying the specification of various flavours of ANOVA, and providing SPSS-like output (including effect sizes and assumption tests), among other features. The ezANOVA() function ... |
How should I define a model formula in R, when one (or more) exact linear restrictions binding the coefficients is available. As an example, say that you know that b1 = 2*b0 in a simple linear regression model.
|
In their great book "Wavelet methods for time series analysis" (2006), Percival & Walden state on p. 83 that the first-round pyramid algorithm scaling filter coefficients $\tilde{V}_{i,t}$ can be approximated by
$$\frac{1}{N} \sum_{k=-\frac{N}{4}+1}^{\frac{N}{4}}{\chi_{k}e^{i 2 \pi t k/N}}$$
arguing that $2^{1/2} \tild... |
A physics application I'm using reports for a first order fit of the three points below as $11.388612x - 301.878$.
x, y
35, 0
430, 4861
656, 7000
It also shows a field labeled: "RMS: 329.499"
How is that RMS calculated? I tried RMSD as defined here but didn't get the same value.
|
I used the lmer function in the lme4 package in order to assess the effects of 2 categorical fixed effects (1º Animal Group: rodents and ants; 2º Microhabitat: bare soil and under cover) on seed predation (a count dependent variable). I have 2 Sites, with 10 trees per site and 4 seed stations per tree. Site and Tree ar... |
As the question states - Is it possible to prove the null hypothesis? From my (limited) understanding of hypothesis, the answer is no but I can't come up with a rigorous explanation for it. Does the question have a definitive answer?
|
I'm doing a time series analysis. I'm doing most of my analysis in R, where I can use "NA" to represent "not available" (e.g. a missing data point). But I'm doing some data preparation in OpenOffice; currently, I'm leaving cells blank for missing data. Is there a better way to "declare" that a cell is NA?
|
We are analysing the effects of different harvesting intensities on soil nutrients. Data was collected over three different years. The first year was before treatments were applied, and the second and third years were 1 year and 6 years post treatment. There are 4 stand types (each replicated 3 times), 6 treatments (r... |
Is there a visualization model that is good for showing the intersection overlap of many sets?
I am thinking something like Venn diagrams but that somehow might lend itself better to a larger number of sets such as 10 or more. Wikipedia does show some higher set Venn diagrams but even the 4 set diagrams are a lot to ta... |
I have a time series and I want to subset it while keeping it as a time series, preserving the start, end, and frequency.
For example, let's say I have a time series:
> qs <- ts(101:110, start=c(2009, 2), frequency=4)
> qs
Qtr1 Qtr2 Qtr3 Qtr4
2009 101 102 103
2010 104 105 106 107
2011 108 109 110 ... |
When computing the difference between means I can resolve a new mean, variance, standard error of the mean, and margin of error, but is there a way to compute a new/composite sample size value?
I ask because I use the difference between means as a way to calibrate the mean and later when comparing other calibrated mean... |
In a field experiment involving crops, what is the difference in considering block as random or otherwise as fixed factor?
As far as I understood, random means that conclusion can be extended to other levels not included in the study; fixed factor on the contrary restricts the analysis only to a specific experiment.
|
I have a problem. I am creating a wide barplot (50x grouped 4 columns) and printing it to ps. However the figure does not fit to printed ps - the x axis goes out of a page. It would fit if only I could remove a large left margin on yaxis. But I have no idea how to move picture left and reduce the margin. I have spend s... |
I have a clustering algorithm (not k-means) with input parameter $k$ (number of clusters). After performing clustering I'd like to get some quantitative measure of quality of this clustering.
The clustering algorithm has one important property. For $k=2$ if I feed $N$ data points without any significant distinction am... |
You are in an exam, and are presented with the following question:
Write down what mark do you expect to
take in this exam... If you get it
right in range of +/-10 % then you
will take 10% bonus... if wrong (or
not answered) you will lose 5%
Assume that you have no idea of how you are going to perform in this... |
I have a very unbalanced sample set, e.g. 99% true and 1% false.
Is it reasonable to select a balanced subset with a 50/50-distribution for neural network training? The reason for this is, that I guess training on the original data set may induce a bias on the true-samples.
Can you suggest me some literature that cove... |
I would like some help with the following problem.
I have 40 subjects. On each subject I take a measurement at 25 body
sites. The measurement is a continuous variable that varies between 0 and 1 and appears to be normally distributed. I want do a test to see if body site statistically significantly affects the measur... |
I'm searching how to (visually) explain simple linear correlation to first year students.
The classical way to visualize would be to give an Y~X scatter plot with a straight regression line.
Recently, I came by the idea of extending this type of graphics by adding to the plot 3 more images, leaving me with: the scatter... |
I am currently collecting data for an experiment into psychosocial characteristics associated with the experience of pain. As part of this, I am collecting GSR and BP measurements electronically from my participants, along with various self-report and implicit measures. I have a psychological background and am comforta... |
I am a very beginner of statistic. Recently a project require me to analyse data using logistic regression & SPSS within a specific time frame. Although I have read few books, but still very blur on how to start off. Can someone guide me through? What is the 1st ste and what next?
Anyway, I have started some. Once ente... |
I'm working through a practice problem for my Stats homework. We're using Confidence Intervals to find a range that the true mean lies within. I'm having trouble understanding how to find the required sample size to estimate the true mean within something like +- 0.5%.
I understand how to work the problem when the rang... |
I'm fooling around with threshold time series models. While I was digging through what others have done, I ran across the CDC's site for flu data.
http://www.cdc.gov/flu/weekly/
About 1/3 of the way down the page is a graph titled "Pneumonia and Influenza Mortality....". It shows the actuals in red, and two black sea... |
What analyses can be used to find an interaction effect in a 2-factor design, with one ordinal and one categorical factor, with binary-valued data?
Specifically, are there any types of analyses that are capable of dealing with a 2 factor design 5(ordinal) x 2(categorical), where the outcomes are either true or false?
O... |
Google Prediction API is a cloud service where user can submit some training data to train some mysterious classifier and later ask it to classify incoming data, for instance to implement spam filters or predict user preferences.
But what is behind the scenes?
|
NOTE: I purposely did not label the axis due to pending publications. The line colors represent the same data in all three plots.
I fitted my data using a negative binomial distribution to generate a pdf. I am happy with the pdf and meets my research needs. PDF plot:
For when reporting the CDF, should I use the empir... |
Let $t_i$ be drawn i.i.d from a Student t distribution with $n$ degrees of freedom, for moderately sized $n$ (say less than 100). Define
$$T = \sum_{1\le i \le k} t_i^2$$
Is $T$ distributed nearly as a chi-square with $k$ degrees of freedom? Is there something like the Central Limit Theorem for the sum of squared rando... |
Although this question is somewhat subjective, I hope it
qualifies
as a good subjective question according to the faq guidelines.
It is based on a question that Olle Häggström asked me a year ago
and although I have some thoughts about it I do not have a
definite answer and I would appreciate some help from others.
Bac... |
I am referring to this article: http://www.nytimes.com/2011/01/11/science/11esp.html
Consider the following experiment. Suppose there was reason to believe that a coin was slightly weighted toward heads. In a test, the coin comes up heads 527 times out of 1,000.
Is this significant evidence that the
coin is weighted... |
I was reading through a paper and I saw a table with a comparison between PPV (Positive Predictive Value) and NPV (Negative Predictive Value). They did some kind of statistical test for them, this is a sketch of the table:
PPV NPV p-value
65.9 100 < 0.00001
...
Every rows refers to a particular contingency ... |
A signal detection experiment typically presents the observer (or diagnostic system) with either a signal or a non-signal, and the observer is asked to report whether they think the presented item is a signal or non-signal. Such experiments yield data that fill a 2x2 matrix:
Signal detection theory represents such dat... |
In 1999, Beyer et al. asked,
When is "Nearest Neighbor" meaningful?
Are there better ways of analyzing and visualizing
the effect of distance flatness on NN search since 1999?
Does [a given] data set provide meaningful answers to the 1-NN problem?
The 10-NN problem? The 100-NN problem?
How would you experts approac... |
In boosting, each additional tree is fitted to the unexplained variation in the response that is currently un-modelled. If we are using squared-error loss, this amounts to fitting on the residuals from the aggregation of the trees fitted up to this point. I am not clear on whether it is at this point that the shrinkage... |
In response to a growing body of statisticians and researchers that criticize the utility of null-hypothesis testing (NHT) for science as a cumulative endeavour, the American Psychological Association Task Force on Statistical Inference avoided an outright ban on NHT, but instead suggested that researchers report effec... |
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