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

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19 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, ...
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1answer
11 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 ...
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0answers
5 views

correlation for moderating variable [on hold]

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 ...
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0answers
12 views

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

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 ...
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1answer
20 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 ...
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3answers
156 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 ...
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1answer
22 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
28 views

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

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. There ...
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1answer
13 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, ...
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0answers
13 views

predictive validity of personality traits in job performance of employees [on hold]

I am doing Phd research on "Role of personality traits in predicting the job performance of employees". I have a sample of 500 managers and used the big five personality theory to measure traits of ...
2
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0answers
16 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
69 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. ...
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0answers
11 views

How to interpret a rolling correlation?

The Dataset The table above contains hypothetical data about 2 vehicles. Vehicle 1 is following vehicle 2. The data is assumed to be collected every 0.1 seconds i.e. 1 frame is 0.1 seconds long. ...
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0answers
13 views

which statistic should I use for inter-rater agreement on nominal data, multiple responses

I have over 400 open-ended responses. The total has been coded by one rater, and a 10% identical sample of the total has been coded by 2 raters. There is a choice of 14 nominal codes, of which the ...
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3answers
57 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
44 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
35 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
11 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
54 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? ...
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2answers
35 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
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154 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 ...
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1answer
50 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
45 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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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 < ...
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0answers
34 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 ...
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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 ...
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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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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 ...
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20 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
11 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
55 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 ...
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6 views

Comparing the means of correlations based on different size of sub-correlations

I would like to compare the mean correlation of two different sample groups: I had two groups of teachers who were judging their students' performance. One group of real teachers (N=10) judged on ...
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9 views

How to assess correlations of 3+ trials per observation?

I'm working with a set of 200 genes. For each gene, I have 3 p values representing independent evaluations of whether that gene shows differential expression under certain experimental conditions as ...
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0answers
9 views

Which method to find which features explain the target?

I have many categorical and numerical features and I sub-selected a few of them by a Random Forest. Now I'd like to determine which features probabilistically(/causally?) explain the target. Something ...
3
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1answer
53 views

What would be an effective strategy to correlate congressional attendance and precipitation?

I have data sets of the attendance of congresspeople, and of the weather in Washington, DC. I would like to examine whether and to what degree precipitation is correlated with the likelihood of ...
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0answers
14 views

Pearson Correlation with symmetric pairs?

I am correlating two features in the leaves of a dendrogram for a given tree distance (2,3,...). When i find the pair "A-B" at distance x I will also have the duplicate "B-A" in the same set for ...
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0answers
14 views

Using bootstrap to compare two ensemble correlations

I am asking for your help because I'm not sure whether the procedure I'm using is correct. I have two models, M1 and M2, and for each of them I have ten instances (ensemble members). For each model ...
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5answers
296 views

Is using deciles to find correlation a statistically valid approach?

I have a sample of 1,449 data points that are not correlated (r-squared 0.006). When analyzing the data, I discovered that by splitting the independent variable values into positive and negative ...
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0answers
23 views

Correlation tests – multivariate correlation matrix?

I just got comments from a reviewer to a submitted article and didn't understand what I should do very well. Here are the tests I performed: We first used principal components analysis (PCA) to ...
2
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2answers
48 views

How do you calculate the statistical significance of a correlation between $Y$ and $X$?

Can one just fit a linear model between $Y$ and $X$, and then take the p-values of the $t$-test done on the slope (or beta) of the linear model? Since presumably correlation would be in the same ...
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1answer
41 views

Differentiate two corelated variables

I am working on a prediction problem. I have a programming background and a small statistics one. If I have two dependent variables and one independent one, how do I work out if the two are ...
2
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2answers
73 views

Best transformation for sinuous data sets?

I am analysing annual behavioural patterns and am currently scratching my head over how to best transform data to test for correlation where my independent variable is the moon phase (given as ...
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0answers
54 views

Finding correlations among many variables

I have 60 variables (each has 100 numerical data points) which could go up as high as 200 variables. I would like to run a test and see if there are any relationships between them. E.g, if variable A ...