Questions tagged [subset]

One set, A, is a subset of another, B, if and only if all elements of A are elements of B.

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110 views

Dealing with many NA's in very large datasets for Lasso

I have a few very large and quite "dirty" (survey) datasets. Primarily, there are lots of NA's. These NA's are mostly the result of different questions being asked in different waves. It is ...
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232 views

Separate ANOVAs on subsets of data

I often read that, after obtaining complex (e.g., four-way) interactions in a factorial ANOVA, researchers decide to split their data by a factor (e.g., gender) and run separate ANOVAs for these two ...
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66 views

Is it appropriate to include overlapping sub-scale scores and total-scale scores in a meta-analysis?

Question, brief In a single multi-level meta-analysis, is it appropriate to include subscale scores (which represent part of a measure) in addition to total scale scores (representing the full ...
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79 views

How many subsets have n values greater/lesser than values in remaining subset?

For example, given set of ten numbers: {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} Split into two equal-sized subsets. Multichoose calculates 252 configurations of subsets with 5 values (pick 5 from 10). Only ...
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790 views

Comparing a subset of a population with the entire population?

Is it possible to compare and test actual subsets of a population to the entire actual population? That is, let's say for a baseball team we want to know which players are contributing to the team's ...
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146 views

Vapnik-Chervonenkis Dimension

My question has to do with the VC dimension of the class of convex polygons with $m$ vertices. A solution to this problem is given in the following: Advanced Algorithms. Call the class of all ...
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267 views

Similarity metric for sets of sets of nominal data

I felt it important to include the full motivation for my question, since part of my trouble I think is simply not knowing the terms to search for. Similarity of set of sets and Similarity metric ...
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353 views

How can I perform a two-sample multivariate t-test where one group is a subset of the other?

Is it possible to compare two means (ideally multivariate) where one comes from a group that is the subset of the other group? E.g. the first group consists of A, B, C, D, E subjects and the second ...
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57 views

How do I use the data from a full sample to inform my estimates about a subgroup?

Consider a sample of size $N$ with various observed characteristics: for example, gender and blood pressure. For the overall sample we have the average $\mu$ and standard deviation $\sigma$ of blood ...
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1answer
24 views

Unsupervised Subspace learning for different Tasks

once we extract subspaces(subset of features) for a dataset using unsupervised learning, can we use them for any task I mean for classification, clustering, or outlier detection? Is the selection of ...
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105 views

Q: AUC of each subgroup is smaller than overall AUC

I have a validation data set of 29242 patients, with known labels/health outcomes and predictions that were generated by some model. 28626 patients are negative and 616 are positive The overall AUC is ...
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1answer
11 views

Inferential considerations when comparing a group against the total

I want to compare the value of a subgroup against the same value in the total population in a regression setting. The easiest way to do it would be to treat the subgroup and the total dataset as two ...
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78 views

Why do subset selection linear models have higher variance than the full model?

I do not get the meaning of this sentences from the Elements of Statistical Learning book when talking about subset selection methods before introducing shrinkage methods. By retaining a subset of ...
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24 views

L sets and Probability theory

I am required to prove the following: Let $L_1$ be the space of real-valued random variables on $(\Omega,\mathscr{A},\mathbb{P})$ which have finite expectation $\mathbb{E}(|X|)<\infty$ and let $...
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42 views

Sample subsets with distribution proportional to elementwise product

I have a set of $n$ elements, $x_1,x_2,\dots,x_n$, each with a weight $w_1, w_2,\dots, w_n$. I want to sample a subset of fixed size $k$ such that the probability of drawing $\{x_a,\dots,x_b\}$ is ...
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17 views

k-means and (re?) standardisation of a sub-set

I have data which is customer purchases of items in each of three months: I have summed the data over the three months for each customer; calculated the proportion of purchases that each item ...
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58 views

Probability that 3 out of 4 sets have non-empty intersection

I have $4$ randomly sampled subsets from population set $S = \{1,2,...,100\}$. Each subset has size $24$. What is the probability that at least one element is common among $3$ out of $4$ subsets?
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19 views

Subset with largest information gain

I am competing in a programming contest where the submission phase can be stated abstractly as follows : There is a known universe set, $U$, and a hidden target $T \subset U$. I submit $S \subset U$, ...
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47 views

Heteroscedasticity in Data, none in Subset

This might seem like a trvial questions to some but sadly not me. My dataset has heteroscedasticity and therefore I use a heteroscedasticity consistent standard error estimator (I use the RLM macro ...
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16 views

Store outputs of Lm performed on conditional dataframe subsets?

I am trying to store the regression's slopes of two variables recorded for different individuals through a season. What I would like is the slope of the regression for each individual for each day (...
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192 views

Find a subset of input data space with high classification accuracy?

I'm having what would seem to be quite a general and widely applicable problem but I can't find literature on the subject. Example problem: Imagine I have medical records of thousands of patients (...
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12 views

How to properly select elements to tag manually for building training and test sets?

I have to select a subset (short texts like comments and twitter posts) out of a huge population to tag them manually for building a sentiment analysis training and test set. How should I select these ...
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45 views

Significance for the whole dataset of detections in a subsample

I have a fairly simple question, but I am not so familiar with these problems so I would like to ask. If I have, let's say, 4 data samples belonging to the same overall population. If in a test a ...
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129 views

comparing ranks for a multinomial distribution between sample and population

I have a known multinomial distribution of a population due to a census. I want to compare a sample with this population. I want to know the probability that the same ranking of the classes of the ...
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81 views

Subset based on maximum difference for one variable, minimum for others

This seems like it should be an easy problem to solve, but I can't think of anything nor can I find anything to help me. I'm working with multiple data sets where I have a series of sometimes ...
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19 views

Assessing stability of a method to less data (subsets of it)

I'm working on a (computational biology) method which provides a result given a set of data regarding a cell. For example, it takes a picture of an object (or a part of it) and assesses the object's ...
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119 views

Learning if instances from a dataset are part of the same subset

I was wondering if there are some well-known machine learning methodologies for subset learning. In other words, to learn if two instances are part of the same subset or not (boolean label?). One ...
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805 views

Cross-validation for best subset selection

Rephrasing my question: I have predictors $\mathbf{X}=(X_1,X_2,X_3,...)$ and want to find the best subset for predicting some variable Y. My interest lies not in linear prediction, but using nearest ...
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46 views

Need to determine stability of a measure over subsets

I have a measure that takes a set of data and spits out a value. I want to determine the stability of this measure in terms of the size of the dataset. I.e, I want to understand how the returns (for ...
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61 views

Finding a Random Variable $X$ on the sample space with given cdf

I will state the problem first, then follow through with my work. Q: Suppose that the sample space is given by $S={w_1,w_2,w_3}$ where $w_1,w_2,w_3$ are three states of tomorrow's weather. We have ...
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47 views

Relationship between P(A|X,Y), P(X|Y) and P(A|X)?

My statistics training is only basic, so forgive any embarrassing misunderstandings. Here's my situation: I have a graph (a big one) with 20,770 nodes. This is Y. I have a subgraph, X (subset of Y),...
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60 views

How to determine the proper sets or subsets of outcomes when autocorrelating frequency of each from year to year

I am trying to determine whether a baseball player has the ability to influence the outcome of an "at bat" by calculating the correlation coefficient between the percentage of at bats which result in ...
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150 views

Probability of drawing some number when randomly selecting subsets of size L

I am trying to find a way to solve the following problem : I have some set A, which contains a set of N numbers, X, where Xi is a number within X. The numbers in X are unique and they are in ...
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17 views

Need help understanding paper by Jolliffe - various methods in choosing subsets for PCA

There's a paper I'm trying to base some work off of called Variable Selection and the Interpretation of Principal Subspaces which uses some various methods to choose subsets of variables. Their ...
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7 views

Uncertainty when taking the difference between a measurement and a subset measurement

Lets say I collected $\mathbf{N_t}$ data points for an experiment and this resulted in a measurement of $A\pm\sigma_A$. Then I'm interested in how a particular variable effects the study and remove $\...
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14 views

Maximizing a subset's variance

Consider the given set [x_1, ... , x_n]. For a fixed natural number M, I want a subset [x_(i1), ..., x_(iM)], whose cardinality ...
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12 views

How to test if the subset is representative to whole dataset

I would like to ask how to test if the subset is representative to the whole dataset. I have for example 150 values in whole "population" and I selected (not randomly) 30 of them. I would ...
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16 views

Reduced chi-squared for models fit to different subsets of data

I have some data to which I am fitting piecewise linear models. I want to select different subsets of the data, fit a model to each of them, and then compare which subsets are best able to be ...
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9 views

Subset dataframe by conditioning on two observations within a column for each subject (group)

I am looking to compare the results of a survey (not shown) before and after teaching. You can see below that the last column column specifies whether this observation contains the information from &...
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11 views

Check if a subset is significantly different from the dataset

I have a dataset with violence rate per City that can be grouped by State. I need to check if any State has significantly different violence rates than the entire dataset. How could I achieve that? ...
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73 views

GLM in R: Subset Covariate to specific factor Levels

I like to conduct a GLM in R like this: glm ( Y ~ X + Z + a + b + c + d, quasipoisson(link="log")) with Y as dependent Variable (Count Data, integer) X as ...
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27 views

Difference between stratification and subset

This may be a duplicate question asked differently, I am curious to know the difference between performing an analysis by stratification on a variable and by subsetting the dataset based on that ...
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1answer
70 views

How to test that a subset of data is distributed no differently than original (discrete, not normal)

In the research I am doing we have initially had ~600 samples which had a certain distribution (not normal, although close). The characteristic of these samples that I am interested in is discrete (...
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1answer
35 views

Compact encoding (vectorization) of unbounded sets

Question I have a set of sets. Each set is unbounded. I would like to find a methodology to encode (vectorize) each subset. I am more specifically interested in memory efficient solutions. ...
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64 views

Problem with significance of results from regression on subset of data

I have performed a hedonic regression with a database where all the variables are very significant and according to the calculations made in R with a squared R = 0.6123. I have performed the same ...
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27 views

Represent roles intersections

I have 11 roles, who defines rights (read, edit, write) on my application. For exemple I have "Inventory" who contains ressources_read and ...
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36 views

Determining whether it matters which subset I pick from my dataset

I'm going to simplify my own research problem with the following example: Lets suppose I have N=40 students in my classroom. I need to select 20 of them to participate in a national math competition. ...
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1answer
34 views

Dividing datasets into fully-correlating subsets

I have a dataset of $N$ variables of which I know that (at least) one combination of their disjoint subsets results in non-negative correlation coefficients for all variables in these subsets. The ...
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103 views

Finding p-value of similarity between 2 networks

So, I want to calculate p-value of a case if possible. Suppose I have: set A with 1,295 elements set B with 493 elements number of same element between set A and B (intersection) is 478 From each ...
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189 views

How to test whether subgroup is influential in overall group mean? (whether removing a subgroup affects results/all-but-subgroup mean != overall mean)

This question is similar to this one but I want to test whether the all-but-subgroup mean differs from overall group including the subgroup. This is DIFFERENT FROM THAT QUESTION in that the question ...