A measure of the degree of linear association among a pair of variables.

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11 views

How to specify binomial glmm with random and correlation in R?

I am working on developing a model with a binomial response variable. My data consist of GPS points from tracked animals. The data set is large and contains 15,000 observations from 40 individuals. I ...
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2answers
24 views

Significant difference and correlations [on hold]

Something just came across my mind... Is it true that when there's no significant difference between groups then there will be correlations between groups? Can anyone clarify this?
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21 views

How would I correlate many variables to a few coefficients?

I'm trying to predict the "strength" vs "tempertature" and "time" curves of some chemical compounds as a function of the concentrations of their component substances. I have 20 different substances. ...
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0answers
7 views

Represents istances with multiple values for an attribute and similarity between them

In the scenario in which I'm working each entity could be represented in terms of ten distinct properties that I will call p1, p2, ..., pn. For each of them, an entity, can have its specific range of ...
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0answers
15 views

Statistical thresholds for large time-series

I am working with matrices, of the size N*M, where each cell corresponds to the Pearson's correlation between two time series. I want to threshold each matrix such that it would retain only ...
2
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1answer
28 views

Is positive coefficient of price correct in a multiple regression model

I am currently undertaking forecasting of energy sales (kWh) for our industrial customers. From historical data gathered from 1993 to 2013, a graph of price per kwh against sales kwh shows a positive ...
2
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1answer
32 views

Exact central confidence interval for a correlation

I am working my way through (T.J. Diccio & B. Efron, "Bootstrap Confidence Intervals", Statistical Science, 1996, 11(3), 189–228), and I'm stuck even before I get to the good stuff. In the ...
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9 views

Inner-line correlation (consistency)

In this paper, I found a quite interesting approach concerning measurement of consistency in survey data (provided that each line=case represents a participant). Still, I cannot figure out exactly ...
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1answer
35 views

Beginner question: finding correlations with percentage data

I am trying to work out whether mobile, desktop or tablet users are more likely to perform an action on a site. The data I have is structured as follows: ...
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23 views

a question about variance, covariance and correlation [on hold]

Stock A and Stock B have a covariance of 0.87. The correlation between them is 0.03. If the variance of Stock A is 36. what is the variance of Stock B?
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15 views

Create correlation map [on hold]

I'm aware that you have a post on almost exactly the same topic, but after many trials I failed to run (or plot?) it successfully. When running ...
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1answer
28 views

Confusion regarding correlation and correlation coefficient

Can somebody provide an intuitive difference between correlation and correlation coefficient? During learning of weights of neural network, I want to show how closely the estimated weights are to the ...
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0answers
14 views

intuition and effectiveness [on hold]

I want to find Relation between Intuition and effective skills for managers. I used Cameron's and Whetten's questionnaire to gather data about effective skills for managers and Agor's questionnaire ...
0
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0answers
23 views

Correlation coefficient for data table

I would like to display correlation coefficients in a table (ideally - with p-value). However, my code produces exactly the same values for each period (so something is obviously wrong). Could you ...
1
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1answer
23 views

Have conducted a bivariate correlation - want to identify the outlier - is there a 'statistical' way to do this?

I run correlation (on SPSS) between a governance indicator 1996 and the same governance indicator in 2012. As would be expected there is a near perfect correlation. What I am interested in, however, ...
0
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0answers
23 views

Iterative Addition of Variables to Model Based on P Value

Suppose I have 64 columns that I have chosen out of 500+ columns based on the fact that they have the highest pairwise correlation (is this a good way?). I take 16 of these columns and run a simple ...
0
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1answer
16 views

Dynamic Time Warping for irregular time series

I have been reading a lot about Dynamic Time Warping (DTW) lately. I am very surprised that there is no literature at all on the application of DTW to irregular time series, or at least I could not ...
0
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0answers
6 views

correlation for moderating variable [closed]

i have to ask about deriving coorelation in spss. Is there any separate method to have correlation of the moderating variable? if yes then guide me little. and secondly, if i have to find out ...
0
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0answers
16 views

Finding correlation of independent variables with a response variable in R [closed]

I am very new to R and statistics. In my current project, I have a dataset as follows. There are independent variables, X1, X2, X3, X4,...,Xn that might or/might not be correlated. There is a ...
1
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1answer
38 views

Estimation of regression with autocorrelated errors

In a book it is written that, In regression work we typically assume that the observational errors are pairwise uncorrelated. But in most time series data , the successive residuals have tendency to ...
11
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3answers
220 views

Real examples of Correlation confused with Causation

I'm looking for specific, real cases in which a causal relationship was inappropriately inferred from evidence of a correlation. Specifically, I'm interested in examples that meet the following ...
0
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1answer
27 views

Fisher's z-transform in Python?

I want to test a sample correlation $r$ for significance ($n=16$), using p-values, in Python. As I have understood from this question, I can achieve that by using Fisher's z-transform. Is there a ...
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1answer
39 views

What Statistical method is necessary to determine the correlation amongst a set of individual correlations? [closed]

I have a question regarding the statistical method necessary to determine a correlation between a set of individual correlations. Below is an example of a situational question I currently face. To ...
0
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1answer
15 views

Utilizing A Correlation Matrix Derived from a Sparse Matrix

I have large correlation matrix in Excel that I'd like to use to inform my choice of explanatory variables in a multiple linear regression model. One problem is that the initial data was very sparse, ...
2
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0answers
22 views

Is it a reasonable rule of thumb to examine Pearson and Spearman correlations, and use the latter if they are very different?

The data I am using is continuous, and may be somewhat skewed, but probably will not have many outliers. It's been suggested to me that it would be a good rule of thumb to examine both Pearson and ...
2
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1answer
13 views

Small number of points driving correlation

I am currently looking at trying to find high correlations in a series of data. I initially just thought I could check the correlation of the data and choose those with the highest correlation but ...
0
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1answer
26 views

Correlations within Factor in a pscyhometric instrument

I am working with results of a psychometric test. There are twelve factors and each have three subfactors. My problem is that one of the subfactors correlates very highly 0.3 to 0.7 with subfactors of ...
2
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2answers
76 views

mediator or moderator variable?

I have been given a set of data and I am confused as to whether one of the variables is a moderator or mediator variable. The hypothesis is that stress and well-being have an inverse relationship. ...
2
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3answers
65 views

Similarities and differences between correlation and regression

If I want to investigate how two continuous variables are linked, what is the difference between calculating the correlation coefficient (Pearson's r) versus calculating the (simple linear) regression ...
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2answers
46 views

Next steps after obtaining a significant Pearson coefficient

Lets say I have an R value of .5 and therefore an $R^2$ value of .25, and a p value < 0.001. (All through the stock cor.test function in R). Is there a way to isolate those cases/observations ...
0
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1answer
38 views

Getting all zero correlations,$\rho_{ij}=\frac{\mathbb cov(e_i,e_j)}{(V(e_i)V(e_j))^{1/2}}$

Consider the general regression model $$Y=X\beta+\epsilon$$ where, $Y$ is an $(n\times 1)$ vector of observations, $X$ is an $(n\times p)$ matrix of known form, $\beta$ is a $(p\times 1)$ vector ...
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0answers
12 views

Comparing two pearson coefficents w/ r^2

I have three variables, x,y, z. My sample n is about 17,000. My pearson coeficients & r^2: for x -> z it is 0.187, 0.034 for y -> z it's 0.311, 0.096 testing for significance, I receive a ...
3
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1answer
31 views

Pearson Correlation for Clustered data

I have a sample that was drawn using cluster sampling. Let say I have variables x and y, and I would like to check the significance of correlation between those two variables in SPSS 20 taking into ...
2
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1answer
57 views

Value of r, i.e. correlation coefficient, of data points on a horizontal straight line

1) If we use the formula $$r = \displaystyle \frac{\displaystyle\sum_{i=1}^n \left( x_i - \bar{x} \right) \left( y_i - \bar{y} \right)}{\sqrt{\displaystyle \sum_{i=1}^n \left( x_i - \bar{x}\right)^2 ...
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0answers
10 views

Difference between cross-correlations for two random variables and two probability functions.

Let me ask basic questions. Q1) What is the difference between cross-correlation between two random variables and cross-correlation between two probability functions for the two random variables? ...
0
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2answers
37 views

Correlation between unordered categorical variable and numerical variables

I have a dataframe with many observations and many variables. Some of them are categorical (unordered) and the others are numerical. I'm looking for associations between these variables. I've been ...
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20 views
3
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3answers
155 views

Correlation in linear regression

I once heard the following statements about the "correlation" in the context of regression. correlation only measures linear relationships $\text{corr}(X,Y)=0$ does not mean the variables are ...
2
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1answer
51 views

Interpret Pearsons correlation output from R

I have conducted Pearson's correlation in R and need help interpreting the results. ...
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2answers
50 views

Correlation analysis: Spearman's $\rho$ is significant, but Pearson's $r$ is not - with likert scale

I am doing a correlation analysis testing summated likert scales. However, one of the correlation analysis shows an unsignificant pearsons r (p = 0.068), BUT spearman's rho is 0.044. What should I ...
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0answers
47 views

If $X, Y$ are jointly standard normal with correlation $r$, and $a, b$ are constants, what is $p(Y < b | X < a)$?

The application here is interpreting the correlation coefficient $r$ in terms of $X$'s ability to predict $Y$ for extreme values of $X$. For example, if $r = .8$, then what is $p(Y < 0 | X < ...
2
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0answers
35 views

Correlation vs Partial Correlation to explore relationship in data

I have a cognitive architecture solving a set of tasks. Also I have data of human subjects solving the same set of tasks. Now I want to see whether I can find a relationship between the performance ...
1
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1answer
22 views

Using more measurements of lower quality or just the one with the best quality?

I am currently trying to analyze some pupillometry data. The device I use gives me X and Y measurements of the pupil area (from which I compute the total area via $A = \pi \times ...
1
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1answer
27 views

How can I determine if two features, given a set of data, are the same feature or not?

Thanks in advance for the help. Suppose I have a set of data of the form [feature, rating]. For the sake of argument lets assume feature can be movie A or movie B and rating is a ranked, continuous ...
2
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1answer
47 views

What is a good way of testing for a relationship between two count variables?

I have counts of occurrences of two types of words (A and B) in several texts. What I would like to test is whether the frequencies of occurrence of both types of words across texts is 'correlated'. ...
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29 views

Can the formula developed by Olkin und Siotani (1964) also be used to compare correlations from Spearman's $\rho$ and Cramér's $V$

The followgin formula is normally used for comparing two Pearsons $r$ correlations: Can this formula also be used to compare correlations from Spearman's $\rho$ and Cramér's $V$?
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0answers
29 views

Graduate research methods: what statistical test should I use?

I hope someone her can help me because I'm so lost. I'm trying to figure out what statistical test I should use for my study: I want to look at how promotions, stadium age, and environmental ...
0
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21 views

Correlation between independent variables in Generalized linear model

short intro: I wish to explain seedling abundance in a savanna ecosystem with two factors. one factor is 'canopy' which is either 0 (under a tree) or 1 (not under a tree). the other factor is distance ...
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0answers
14 views

Convolutional networks: how to deal with duplicate filters?

I have to train a convolutional network. When I visualize its conv filter matrices from a layer, many filters are quite similar, almost equal. 1) Don't you know a common way to detect couples of ...
4
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1answer
64 views

Interpretation of Spearman's rank correlation coefficient - beyond its significance

I calculated the Spearman's rank correlation coefficient interpretation for a given 2D dataset. I then tested its significance by doing a permutation test and obtained a p-value. I have a problem ...