The Pearson product-moment correlation coefficient is a measure of the linear relationship between two variables $X$ and $Y$, giving a value between +1 and −1.

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Error in Pearson correlation, 'y' must be numeric [on hold]

I'm running a regression modelling with GLM between train and validation variables. All the variables are in numeric values. But there is an error when i try to run correlation with an error: 'y' must ...
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25 views

What statistical tests to use?

My topic is on A Study of Budget Slack and the Influence of Budget Participation on Budget Slack. My research objectives are to study the relationship between budget participation, procedural ...
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1answer
99 views

What is the distribution of sample correlation coefficients between two uncorrelated normal variables?

I want to compare observed bivariate (Pearson's $\rho$ and Spearman's $\rho$) correlations coefficients with what would be expected from random data. Assume that we measure, say, 36, cases across ...
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11 views

Is Pearson correlation on graphs a valid approach to compare undirected weighted graphs?

I have came to several instances where researchers use Pearson correlation to compare edges of two graphs to find out if they are similar. For example, given two symmetric adjacency (proximity) ...
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1answer
12 views

converting a chi-square with more than one degree of freedom into a pearsons r

I want to run a power analysis for a study using correlations between two continuous variables. Previous research with the variable I am interested in used a Kruskal-Wallis test to look at differences ...
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1answer
144 views

Two Sample chi squared test

This question is from Van der Vaart's book Asymptotic Statistics, pg. 253. #3: Suppose that $\mathbf{X}_m$ and $\mathbf{Y}_n$ are independent multinomial vectors with parameters $(m,a_1,\ldots,a_k)$ ...
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16 views

Calculate within and between group correlation

MY DATA: A surveys which contains 2 different questionnaires on the same subject which were taken by n=800 patients (i.e., timepoint) (#1 questionnaire: 5 questions which reach a total score of 0-42, ...
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1answer
73 views

K-Means Clustering using modified correlation (1 - pearson correlation coefficient)

I am trying to implement k-means clustering on a 6x6 data set that looks like this: 2 3 6 0 1 7 4 9 9 6 2 2 0 1 7 9 5 0 2 3 2 7 8 3 8 2 9 2 3 1 8 0 0 1 7 9 Using ...
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22 views

pearsons vs spearmans [duplicate]

-two sets of samples (n=10) for each. each set has one outlier. -input is log-transformed and pareto-scaled values of intensity levels of different metabolites in each of the 20 samples, as detected ...
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32 views

Pearson correlation with missing values

I am trying to correlate dendrochronological data with climate data. The first one is acquired directly from trees, the second one from various stations from around the world. According to the formula ...
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8 views

Confusion about Matthew's correlation coefficient being equivalent with Pearson's r

It has been suggested that Matthew's correlation coefficient (MCC) is actually the application of Pearson's r to binary variables (Relation between the phi, Matthews and Pearson correlation ...
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59 views

Why is Pearson Principal Component Analysis so much more common than Spearman or Kendall PCA?

As I understand it, Pearson PCA finds eigenvectors of the Pearson correlation matrix. The result is a coordinate system with dimensions that are linearly uncorrelated. But, a Spearman PCA does this ...
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26 views

Is Pearson Coefficient applicable to my data (mixed variable types)?

TL:DR is Pearson correlation acceptable for a binary variable? For my study I have measured and determined a "change in anxiety" in a group of students (the change has been found significant with ...
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29 views

FDR correction for multiple comparisons with Pearson's correlation and linear regression

I'm trying to correlate a measurement (survival after treatment with 'x') with gene expression data for > 10,000 genes across ~ 30 samples (cell lines) and I think I need to correct the significance ...
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2answers
51 views

How to test the linearity between two non normal distributed variables

I have two variables $(x_i,y_i), \; i=1, \dots 300$ and I would have liked to apply a linear regression on them, but as you can see in the scatterplot below I have a very bad linear trend. As I need ...
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18 views

Comparing two correlation coefficients

I want to do an investigation into the correlation between 2 pointers scored and games won and 3 pointers scored and games won in the NBA. However I have got two questions: I know the process of ...
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27 views

Correlation between time series obtained from multiple subjects, SPSS

I have designed experiment in which all subjects are performing the same exact task, with no variations. The task is a tracking task in which the subject has to keep a marker inside a circle, using ...
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0answers
9 views

statistics to use for a mobile based health intervention aimed to increase physical activity

I am trying to understand how a mobile application will increase the number of steps taken. We are measuring their BMI and waist circumference before and after 6 months and taking measurements of the ...
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16 views

Correlation robust to outliers

I am concerned with Pearson correlation. My idea is to throw away the outliers in terms of absolute value, as it seems appropriate to my case. However, I don't know if I should do it only according to ...
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11 views

Hybrid linear and rank order correlation?

I know that the standard Pearson correlation is useful when the two variables are supposed to have a linearly relationship. I also know that if the absolute value of the variables doesn't matter, but ...
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2answers
71 views

How can I calculate what observation characterizes the relationship of two variables?

I have two variables. Variable 1:The prevalences of infection with Schistosoma (+ve, -ve) Variable 2:Different occupations in a rural area in central Africa (Fishermes, Farmers, Traders, Craftsmen) ...
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1answer
76 views

Visualizing pairwise Pearson correlation between matrices

The task is that I'm trying to assess the degree to which the features in matrix A is captured by the features in matrix B. For each feature in a matrix A I want to find the most strongly correlated ...
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52 views

How to chose the right analysis and tests

In R I have two datasets data1 and data2. The datasets contain data of user, a game they have played, and the number of time ...
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18 views

On interpreting the statistical significance of R squared

I have performed a linear regression analysis to two series of data, each of which has 50 values. I did the analysis in SPSS and as a result got a table which says ...
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1answer
232 views

Pearson correlation coefficient is a measure of linear correlation - proof

Is it possible to prove that Pearson coefficient is a measure of linear correlation between two variables? I think I've seen proofs somewhere that if the relationship between variables $X, Y$ is ...
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16 views

Median Pearson's r calculation with regards to p-value

Assume I do have a bunch of Pearson's r values (say 100) over some experiments with different sample size (sometimes in the 10000s, sometimes just a handful). For each of these Pearson's r values I do ...
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1answer
32 views

How to find out if there is a relationship between 6 independent variables and 3 dependent variables

Let me apologise for being so new to statistics, and ask for your patience and expertise in helping to achieve the following. We would like to ascertain the extent to which any or any combination of ...
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16 views

Contradictory results between correlation tests

I analyzed the correlation between two variables using Spearman's ρ, Kendall's τ and Pearson's r. According to Spearman and Kendall's tests, there is no significant correlation between the variables, ...
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1answer
66 views

bootstrapping spearman vs. pearson multiple correlations

I would like to calculate simple correlations. Since my sample size is quite small and data are not normally distributed I thought about Spearman’s correlations. Then I read about bootstrapping as a ...
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40 views

quantify correlation simultaneously for linear and non-linear trends

Intro Consider the following figure: The red data is my observed data and the blue data is the simulated data. In an ideal case one would expect to detect all the data points. However, in real ...
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1answer
38 views

Study correlation in case of nonlinearity

Looking at the graph, clearly there is a correlation between the $x$ and $y$ values. However, this correlation is not linear, hence it cannot be studied by the ...
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1answer
37 views

What purpose does multiplying by 3 serve in Pearson's second coefficient of skewness?

It can be calculated by $\frac{3\,(\text{mean}-\text{median})}{\text{standard deviation}}$. Does the 3 make the result easier to work with somehow, or what?
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18 views

Spearman's Rank or Pearson's Correlation Coefficient? [duplicate]

I would like to test to see whether there is a significant correlation between the percentage of children in census output areas and the mean distance to green spaces. I'm confused as to whether it is ...
2
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1answer
36 views

Computing Pearson's $r$ with two lines? [duplicate]

Given two regression lines, one for $x$ on $y$ and one for $y$ on $x$, but no actual data points (just the two lines with slopes and intercepts), can I compute Pearson's product moment coefficient ...
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17 views

Use of Correlation

How do we use a correlation score between two variables for analysing data? I have a set of 20 features and need to predict 21st feature. Now is it necessary that correlation between any two features ...
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2answers
30 views

Correlation among data - suggestions

I would like to have your help for (simple) correlation problems. I've data about the measurement of some substances in the organs of animals (more than 20 samples).My data are obtained by different ...
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23 views

Is partial Pearson correlation considered as a linear measure of association?

I know Pearson's correlation is considered to be a linear measure of association, for it is intimately linked to simple least square regression. It is known to have poor performance on non-linear data ...
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2answers
65 views

Is it valid and/or accurate to calculate Pearson/Spearman correlation with only a few (e.g. 6) values?

Suppose I have two variables, x and y: say, x=[34,45,22,11,67,89] y=[14,56,23,56,89,34] Taking Pearson's correlation between these two values gives 0.24. Is this valid and/or accurate measure ...
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Can Cronbach’s alpha be used to assess the equivalence of two different questionnaires?

I have a very simple quality-of-life (QOL) questionnaire that is much easier to implement than two currently used in practice and a longitudinal data set in which patients were administered all three ...
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1answer
76 views

Linear transformation effect on Pearson's r

To my understanding multiplying all x (or all y) values in a constant will not change |r|. I'm looking for formal proof.
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1answer
26 views

To determine if standing broad jump performance is associated with body mass?

If the data for body mass is not normal, and the data for standing broad jump is normal. What should i do?
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15 views

Two different Correlation? [duplicate]

I don't understand, what is the the different between the Pearson Correlation and Spearman rho, except the mathematical calculation? Thanks!
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2answers
22 views

Correlation between sampled percentages?

I have two statistics from a range of districts obtained by sampling from the total district population e.g. number of doctors per district and the gender of these doctors. Now I want to see whether ...
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1answer
30 views

Automatically find the best growth (linear, quadratic, exponential, etc.) to fit the points [duplicate]

Suppose there is a set of points $[(x_1, y_1),(x_2, y_2), ..., (x_n, y_n)]$. I want to figure out whether $y$ will grow with $x$. If yes, I want to automatically find the best growth (linear growth, ...
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59 views

How to assess correlation in non-ordinal (non-ranked) and non-normally distributed data?

Looking at Person's, Spearman's and Kendall's correlation coefficients for the same data, we can see that both Spearman's Rho and Kendall's Tau misrepresent the acutal correlation, if the data is ...
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51 views

Nearly perfect correlation observed in the real world

I am searching for nice examples from the real world where the correlation in terms of the Pearson product-moment correlation coefficient is nearly perfect (like 0.99 or something doesn't really ...
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52 views

Correlation for a sample with constant dependent variable

Generally, I am trying to calculate correlation coefficients (best case even Pearson r) of several independent variables on one single dependent variable. I am looking at several studies, where some ...
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0answers
92 views

performing a partial correlation using cosine similarity

I wonder if it's possible to carry out a partial correlation using correlation measures other than the Pearson or Spearman correlation. In particular, I want to assess the cosine similarity between X ...
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1answer
50 views

Different value for Pearson $\chi^2$ in chisq.test() and loglm() from MASS

I realized that the Pearson's $\chi^2$ statistic obtained by chisq.test() is different than the one obtained using loglm() from ...
2
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1answer
66 views

convergence rate of Pearson correlation

I am looking to find the finest bound possible for $$\mathbb{P}\left( | \hat{\rho}(X,Y) - \rho(X,Y) | \geq t\right) \leq ?$$ where $\rho$ is the Pearson correlation defined as $$\rho(X,Y) = ...