Questions tagged [non-independent]
Data, events, processes, etc, are non-independent if knowledge of 1 provides some information about the state or value of the other.
573
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How to conduct sensitivity analyses for cluster / sample in three-level meta analyses in metafor?
Problem
am wanting to do a leave1out sensitivity analysis of an rma.mv (three-level) meta-analysis, where "1" is a cluster / sample (rather than a single effect size).
I understand that some ...
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27
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Assessing the Impact of a Specific Treatment on Survey Results: A Wilcoxon Signed-Rank Test Approach on Paired Samples
I have conducted a survey with several scale questions ranked 1-10 on a sample of n=18. I applied a specific treatment before and after the survey. However, I'm unsure about how to analyze the data ...
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13
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Using linear mixed models to model nested data
I divided participants into different pairs according to their language proficiency score, and now I ask participants in different pairs to have conversations, so every participant now have a pair ID (...
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36
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Finding inequality relationships in stochastic data
Consider random variables $X_i$ such that the following holds:
$$ a_1 X_1 + \dots + a_n X_n -k \geq 0 + \epsilon $$
where the $a_i$ are constants and $\epsilon$ is random noise.
How is it possible to ...
- 652
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47
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Normality test for non-independent observations
I want to check if my data's distribution is normal. Thought of visual and formal test.
One thing I'm not sure about – my observations are respiratory measurements of patient. Each patient measure ...
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0
answers
8
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Compairing multiple distributions from repeated measures design to a refrence value
I have 24hrs of temperature measurements taken in one minute intervals for a set of individuals. Thus, there is a non-independent distribution of temperatures for each individual as each measurement ...
- 733
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11
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Similarity measure over time
I'm completely new to this so I apologise in advance if my question isn't even phrased correctly.
I want to analyse changes in similarity of two interacting entities over time. Each entity is ...
3
votes
2
answers
72
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Does strict monotonicity imply image variable is dependent with domain variable?
Suppose a random variable $X$ and a strictly monotone (and measurable) function $f$ in which $f(X)$ is always defined.
Does it necessarily hold that $f(X)$ is statistically dependent with X?
I should ...
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compare time-dependent proportions to baseline
I measured changes in the appearance of chronic wounds. There are four levels of this variable that can be ordered from the worst to best as necrotic < sloughy < granulating < epithelialising....
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2
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Calculate ROC probability for highy correlated variables
The usual assumption of i.i.d. is made with such frequency that it risks being applied to things like difference of correlations for highly dependent (correlated) variables. To calculate dependent ...
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21
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Trying to decide whether the sample is dependent or independent
I have a problem deciding whether my data has dependant/pairwise or independant samples.
I have read multiple online guides now, but I can't figure it out:
I am testing about 10 different surface ...
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2
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1
answer
27
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Can we preserve dependence in discretization?
Suppose we have two categorical random variables $X$ and $Y$, with both $k$ levels.
We assume $Y$ is generated causally from $X$ ($X \to Y$). We also assume causal Markovian is satisfied, which means $...
- 361
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23
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Predicting outcome with ordinally, continuously or linearly related predictor variables
I am attempting to predict the number of chicks that will hatch from a group of eggs stored in a box. My predictor variable is the count of the eggs based on their size, such as "THE NUMBER OF ...
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62
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Conducting a regression model with beta coefficients dependent to each other in a nonlinear way (My different independent variables are ordered)
I have a dataset of 1000 previous contests in a giveaway show where the contestant earns a random number of boxes named from "one" to "ten". The boxes contain either 1 or no gift. ...
- 31
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33
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Sample covariance of non-independent Gaussian vectors
Problem definition
Consider the following dataset
\begin{equation*}
\{y_j=m+v_j\}_{j=1}^N
\end{equation*}
of bivariate Gaussian vectors, where
\begin{equation*}
m\sim\mathcal{N}(\hat{m}, P_m)
\qquad
...
- 131
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10
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Can I use linear regression if my dependent variable is ordinal? [duplicate]
My dependent variable is the ranking in search results when searching for a specific search term (so I have data for items that is rank 1-10 search results). I want to check what variables (...
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31
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How to measure distances between sparse vectors when the dimensions are not independent?
I am searching for a similarity metric between vectors that are sparse-ish, but most distance metrics treat each dimension as independent and this can create problems when comparing distances between ...
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0
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30
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How to turn an expectation $E[A]$ into a conditional expectation, e.g., $E[A|B=1]$?
How can you turn an expectation $E[A]$ into a conditional expectation, e.g., $E[A|B=1]$, where:
A - continuous random variable, $A \in (-100, 1000)$
B - discrete r.v., $B \in {0, 1}$
A and B are ...
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0
answers
26
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Model the probability of having an event in the future knowing a past event
I need your help to compute a conditional probability, I'm not very at ease with probabilities and I'm feeling a bit stuck.
Let's suppose $X_W$ is a counter counting some events in a time window $W$. ...
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16
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Transformation of dependent variable
Why do we sometimes transform the dependent variable in a regression analysis as a growth rate?
$$\frac{Y_{it+1}-Y_{it}}{Y_{it}} = X'_i \beta + \epsilon_i$$
instead of:
$$Y_i = X'_i \beta + \epsilon_i$...
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49
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How do I calculate the probability of seeing values in a dependent joint normal distribution? [duplicate]
Let's say A is a normal distribution A = N(mean = 0, SD = 1). Let's say B = A + N(0, 0.5), such that A and B are dependent. What is P(A>1, B>1) (the probability of seeing a point whose A and B ...
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57
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How to analyze repeated cross-sectional survey
I am relatively new to multilevel or mixed effects modeling, and I have been tasked by my employer to analyze survey data they collected from their organization. Their goal is to study the effect of ...
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1
answer
107
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Independence assumption of non-parametric tests (Mann-Whitney & Wilcoxon Signed rank)
I'm interested in testing (one at a time) these two hypotheses using the...
Mann-Whitney U test.
H0: The probability that an observation in Group1 is greater than an observation in Group2 is 0.50
But ...
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0
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What test should be used to test a difference in proportions when some, but not all of the subjects, are the same?
I am interested in testing if there has been a change in the proportion of events after an intervention was put in place (number of events before intervention compared to after). My population is a ...
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0
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12
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How to analyze mean differences between two groups without independent responses?
I have two groups, high quality vs. low quality. I want to see whether the low quality data impact the means of various scales when combined with the high quality data (i.e., high + low quality data ...
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0
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24
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Testing pairwise differences for correlated pairs
Here is my setup:
I have B=100 pairs of samples (a_i1, a_i2) i=1..B
Unfortunately, unlike in classical paired samples, for both ...
1
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0
answers
17
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Employee Satisfaction data collected at two times- samples overlap but are not paired by case-How to compare t1 to t2
It feels like this should be a no-brainer but I just can't see it. I collected employee satisfaction data in year 1 and year 2. I cannot connect subjects across years because I did not assign or ...
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22
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Identify the iv dv between subject and within subject
For each of the below research design examples, indicate the following:
a. Independent variable(s)
b. Dependent variable
c. Whether each IV is between subjects or within subjects
d. ...
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16
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Independent and exclusive for events [duplicate]
In probability theory, I now understand that 'two events are independent' does not mean that 'two events are exclusive' and vice versa.
Now I wonder if the former means the latter is not true, or the ...
- 1,087
1
vote
1
answer
61
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Calculate expectation of a function with two dependent random variables
Hi Cross Validated community,
My question has to do regarding expectation of a multiplication of two random variables that are dependent.
Assume there are two random variables, one discrete: $G \in \{...
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answers
37
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What is the right statistical test, to test differences in group relations
The setup is a group of 4 animals that can choose to spend time together - or not. This continues for several days and afterwards the data is the time of each animal spent with each other.
So 6 ...
- 101
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21
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Sum of Multivariate Distribution with Normal Copula
When summing multivariate distributions that uses a normal copula, is it true that the normal copula part of the distribution remains unchanged?
The R code below simulates from a two-dimensional ...
- 2,227
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33
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Is it OK to use multiple one-way ANOVA over a time course?
Dear CrossValidated community,
I have time series data were the treatment decrease the visible tissue of the sample. I want to find the separation point between control and treatment curves. Initially ...
0
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1
answer
58
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Do linear transforms of IID random vectors make the resulting covariances sufficient to describe statistical dependence?
This question is motivated by the fact that a linear transformation of an IID standard normal vector gives the multivariate Gaussian distribution, and that the statistical dependence of such ...
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50
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How Best to Use the Delta Method to Approximate True Variance in a T-test Given Correlated Data?
Let's say that the analytical infrastructure at my place of work heavily centers around t-tests. I'd like to use this platform to perform a t-test on correlated data, e.g. the extent to which an order ...
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61
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What type of analysis to use for a pre-post test design with paired means and covariates (stata)
I am conducting a retrospective analysis of the efficacy of an intervention with "Therapy A." There is a baseline period and a treatment period, however, all the patients received the ...
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0
answers
34
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Comparing two sample proportions with dependent (?) data
Case:
I want to know whether the proportion of people getting fired is less now than it was in 2019.
I know $\hat{p}$ for both this year and previous years, also I have the sample sizes $n$. I want to ...
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2
votes
1
answer
40
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How can one evaluate the similarity of non-independent data-sets
I have a set of time series from different runs of a computational model. I know that the computational model is highly historical in the sense that the state early in a trial heavily influences (in a ...
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46
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How to deal with oversampling and undersampling of countries to be able to compare them?
I have a dataset that looks like this:
cc
samples
population
% sample
US
100
1,000
1%
CA
20
100
20%
BR
9
10
90%
AU
600
300
200%
I have samples from a certain population and the percentage of ...
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1
answer
39
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Is it OK to re-sample the same patients at multiple points in time and then use the data for classification?
I'm trying to predict which patients will have a bad outcome (BO) within the next 2 weeks based on medical readings (plus some behavioral data) from the last 6 weeks. Total data timespan is 8 weeks, i....
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1
answer
78
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Kaplan Meier (KM) estimator and non independent observations
I have to deal with a statistical issue in a study, specially with the use of Kaplan-Meier estimator in the case of non independent observations.
Background of the study:
We follow-up patients (N = ...
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35
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Non-independence of observations
I have a latent random variable $X_i$ and observations $y_i$, for $1<i<N$. I want to write a model for $X_i$ that provides the density $f(X_i|y_{1:N})$, where $y_{a:b}$ means all observations ...
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Are these two events independent (Comey and Mccabe tax returns)? How would we tell?
The NYT reports:
The former F.B.I. director and his deputy, both of whom former
President Donald J. Trump wanted prosecuted, were selected for a rare
audit program that the tax agency says is random.
...
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0
answers
91
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PDF of the linear combination of two order statistics
I have just started to learn order statistics so please feel free to correct my notation/terminology.
In my field is common to provide data as the median of some sample (for example several ...
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4
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1
answer
133
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How to statistically combine regression coefficients derived from subsamples of data
I wrote a version of this question yesterday, and I think in my effort to be brief, I wasn't clear. So I'm trying again.
I have questions about a cross validation for ensuring the independence of data ...
- 243
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10
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accounting for multi-scale spatial dependency in samples analysis
I have a spatially nested dataset as follows:
5 samples per cluster
5 clusters per plot
4 plots per site (2 habitats per site, 2 plots each)
7 sites overall
I have: 5 samples * 5 clusters * 4 plots * ...
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2
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0
answers
39
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integral related to a general bivariate copula C(u,v) of |u-v|
I'm trying to compute the following integral over the unit square $I^2=[0,1]^2$:
$$
\int_0^1\int_0^1 |u-v|dC(u,v),
$$
where $C(u,v)$ is a generic bivariate copula, which should be equal to
$$
1-2\...
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71
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How to calculate the probability distribution of the sum of two dependent random variables?
I need to calculate the PDF and CDF of the polynomial $c_1+c_2 x^2+c_3 x^4$, where $c_1>0$, $c_2<0$ and $c_3>0$ or $c_3<0$ and $x$ is a random variable following the truncated half nornal ...
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11
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Mixed effects models with dependence between levels of the grouping variable
Let's say that a longitudinal survey allows for re-participation, but in each new participation interval, individuals use a different ID/alias.
Thus, in the dataset, multiple subsets of IDs/aliases ...
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21
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Explaining Variance in Regression Model of highly correlated data
I am currently tracking an Index fund of stock and it's underlying Alpha Factors(Liquidation, Volume, Investor Sentiment etc). I have the historical data of these Alpha Factors, as well as the Index's ...
