# Tagged Questions

English psychologist Charles Spearman is best known in statistics for the Spearman rank correlation coefficient, or Spearman's rho.

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### Multidimensional Scaling in R with Spearman's Rank Correlation

I'm new to MDS, but I found some good starter code here (http://mhermans.net/static/postdata/r-examples/neighbours-mds/neighbours-mds-example.html) and which I borrowed for below. The code works fine, ...
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### How outliers can effect the correlation results (Spearman and Pearson)?

How outliers can effect the correlation results (Spearman and Pearson)? I have two series of data. The source of the data are different but both are temperature that are measured by different ...
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### A question from a test in statistics?

I got the following question in my finals, but the teacher claims I didn't answer this right, I chose a. as the right answer, what is the right answer and why? ...
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### Are 7-point Likert items always ordinal? [duplicate]

I'm doing a study that (among other things) examines the relationship between the quantity of comments students receive in online discussion forums and the following motivational factors: sense of ...
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### If linear regression is related to Pearson's correlation, are there any regression techniques related to Kendall's and Spearman's correlations?

Maybe this question is naive, but: If linear regression is closely related to Pearson's correlation coefficient, are there any regression techniques closely related to Kendall's and Spearman's ...
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### Analysis of compounds using PCA - selecting the right PCA “type” for the data…?

I'm completing scientific analysis of chemical compounds in consumer products. As a non-statistician, I would really appreciate any thoughts from the experts here. My data is non-normal so I've used ...
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### How to manage correlation coefficients (Spearman, Kendall) with lists of different dimensions?

I have to compare two different lists of biomolecular annotations, and to find out their correlation degree. To do this, I have implemented a function computing the Spearman's rank correlation ...
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### Calculating a correlation with yes/no answers?

How do you calculate a correlation, that similar to Spearman and Pearson forumlar when you are only comparing one variable (age) to answer given by yes and no. As ages goes up more likely to answer ...
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### Spearman Rho or ANOVA when examining effect of ordinal IV on continuous DV?

I have an ordinal independent variable (<1hr, 1hr, 1-3hrs, 3-5hrs, >5hrs) and an interval dependent variable (test scores). Apparently I am expected to examine the relationship between the two by ...
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### Are correlations transitive between manifested construct variables and other set of variables?

I have seen here that correlation is not transitive, but I wanted to know if such argument applies when we model our assumptions over a construct. More specifically, in my model, I have a construct ...
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### Understanding the p-value in Spearman's rank correlation

I have some pairs of datasets (n=200 or thereabouts), of samples which are non-negative and not normally distributed. I think these pairs of variables are related, ...
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### Spearman's Correlation using Stata

I am trying to use Stata for the first time to calculate Spearman's Rank Correlation for differences in weight and hemoglobin between annual visits for a small dataset. Do I enter the differences with ...
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### Spearman's Coefficient with excluded ranks

I've got a dataset where I apply one of two transformations to get two scores, Score A and Score B. I then rank Scores A and B and for simplicity's take decide to keep only records where rank(score A) ...
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### How to rank the elements for use in Spearman rank correlation?

If I have 50 items and I want to compare the top 30. I have several cases to do the ranking , so which one is correct? For simplicity I will replace in the example below 50 items with 5 ( A,B,C,D,E) ...
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### How to test correlation between an ordinal and a continuous variable?

Which is the best way to test correlation between what I think it is an ordinal variable (the no of weeks worked out of first 8.. which can take values from 0 to 8) and a continuous variable (the ...
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### Spearman rank recommended n size

Is there a recommended n to test for Spearman's rank correlation? I have 2 lists of around 10,000 items. I read that Spearman's rank correlation is fine between 10-30 , can I use spearman to compare ...
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### Internal reliability for ordinal scale using Spearman correlation matrix

I have a question about estimating the reliability (coefficient alpha) of a pilot scale by assessing its internal consistency. The pilot questionnaire generates ordinal data, 9 items each with 9 ...
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### Spearman correlation in the presence of many ties - how to spot a problem?

I'm testing the hypothesis that there's a monotonic relationship between two variables. I think I should use a Spearman rank correlation test, since my data don't necessarily meet normality ...
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### How to test for correlation with data that violates assumption of linearity and is not monotonic?

I have sampled 8 individuals (birds) from two regions. For each of these 16 individuals I have sampled 9 feathers that have each grown in sequential order (from 1 to 9). Next I have measure both ...
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### What are the main different/alternative correlation estimators?

I'm looking to learn about the main/popular alternatives when it comes to estimating correlations that I've missed in the following list. The best answer will provide a reference (can be Wikipedia), a ...
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### Reporting coefficient of determination using Spearman's rho

I have two non-normally distributed variables (positively-skewed, exhibiting ceiling effects). I would like to calculate the correlation coefficient between these two variables. Due to the ...
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### Problem with Spearman correlation in case of many ties

I'm using the Spearman correlation coefficient test for multiple non-parametric ranked categories in excel. I used the built in rank function in excel to calculate the rank of each individuals but i ...
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### How one can improve correlation (higher rho values) on non normal distributions?

No matter what class or book I see, the normal distribution is always advocated. I have been trying to find ways to assess relationship between variables for non normal distributions, most of which ...
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### Cor.test and statistical test values for spearman correlation, how to make sense of them?

I am trying to make sense of the spearman test I am getting as a result of using cor.test on R package. This page seemed to me to inform that I should care not only for p-values and rho values from ...
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### Can't get observation-wise factor scores from psych package

After R reads the data, say- ...
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### Effect of treatment on correlation between two sets of variables

Imagine I wish to see the effect of some treatment on the correlation between two groups of variables, which I measure with Spearman's rank correlation coefficient. Treatment A gives a Spearman's ...
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### Whether to use Spearman's rho or multiple regression to examine relationship between two Likert scales?

I am doing my thesis and have absolutely no previous experience in statistics. I have constructed several Likert scales by forming composites scores each based on 4-6 items which tests the level of ...
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### What does it indicate when the Spearman correlation is a definite amount less than Pearson?

I have a bunch of related datasets. The pearson correlations between pairs of them are typically definitely larger than the spearman correlations. That suggests any correlation is linear, but one ...
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### I have a statistic, how do I calculate its distribution?

I am comparing images for correlation. The images are all correlated, but I would like to determine when one pair is much more highly correlated, relative to another pair. I am using as a statistic ...
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### Spearman's rank correlation for a beginner: Sample size and Interpretation

I am a computer scientist performing research, which includes calculating the Spearman rank correlation of two lists, one ranked by a human, another by a computer program. I have the following ...
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### Ranked/Ordinal data - 3 variables

I have the following hypothesis: Novice drivers perceive road environments as more difficult when there are more pedestrians. I have the following data: The category each driver falls in to (1. ...
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### Rank correlation and demonstrating reasonable proficiency in rank ordering

Background I'm working on a new effort estimation model (dissertation work) which involves software engineers organizing tasks (rank ordering) in order of increasing effort based solely on their ...
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### Calculating P-value for Spearman's rank correlation coefficient example on Wikipedia

The Wikipedia article Spearman's rank correlation coefficient contains an example for calculating ρ. At the end of the sections is the statement "...with a P-value = 0.6864058 (using the t ...
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### Spearman or Kendall correlation?

I would like to assess the correlation between a 7-category ordinal variable (X) and a number of other variables some of which are ordinal with 3-6 categories, others are continuous and a couple are ...
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### How to calculate a confidence interval for Spearman's rank correlation?

Wikipedia has a Fisher transform of the Spearman rank correlation to an approximate z-score. Perhaps that z-score is the difference from null hypothesis (rank correlation 0)? This page has the ...
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### How does the Goodman-Kruskal gamma test and the Kendall tau or Spearman rho test compare?

In my work, we are comparing predicted rankings versus true rankings for some sets of data. Up until recently, we've been using Kendall-Tau alone. A group working on a similar project suggested we try ...
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### What are other good ways of finding out the degree of similarity between lists?

I have a ground truth list, call it A, and I have different methods for generating lists that should be somewhat similar.. I want to decide which method of these generates a list that is most similar ...
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### Significance test on the difference of Spearman's correlation coefficient

(Thanks a lot for the quick responses! I did a poor job of asking the question, so let me retry.) I do not know how to find out whether or not the difference between two Spearman's correlations is ...
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### How to average Spearman correlations? [duplicate]

Possible Duplicate: Averaging correlation values I have a number of users, and for each user I have 2 ordered lists of items (one is from observation, one is generated by an algorithm). ...
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### Why are all the spearman's rho correlations with one variable low when the other variables all have moderate correlations?

I was wondering what could be the reasons for a very low Spearman correlation, as low as 0.01-0.06. Basically no correlation even exists! All my other variables have moderate correlations except any ...
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### Pearson and Spearman correlations - how to determine if they are “similar”?

I would like to know if there are any rules to determine if Pearson's r correlation values are similar to Spearman's rho? For example, if r = -.207 and rho = -.282, are these similar enough to just ...
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### Can Spearman's correlation be run on z scores?

I understand the logic of standardising raw data that is based on different scales into z scores so that they can compared, for example comparing a score of 75 out of 100 in one test versus 65 out of ...
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### What could cause big differences in correlation coefficient between Pearson's and Spearman's correlation for a given dataset?

The Pearson's coefficient between two variables is quite high (r=.65). But when I rank the variable values and run a Spearman's correlation, the cofficient value is much lower (r=.30). What is the ...
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### How to analyse a study looking at relationship between one set of five items (predictors) and a second set of five items (outcomes)

My study is about customers’ perception of the effectiveness for a Malaysia corporate Weblog. In my study, customers’ perception of the effectiveness defined as perceived ease of use, perceived ...
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### Adjust a large set of Spearman correlation analyses for multiple testing [duplicate]

Possible Duplicate: Threshold for correlation coefficient to indicate statistical significance of a correlation in a correlation matrix Context I am doing an exploratory study to ...
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### Spearman correlation of two Weibull distributions

Is there a way to find the Spearman correlation between two Weibull distributions? I need it as a parameter in a copula function for the joint Weibull distribution. I learned that using the Pearson ...
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### How to choose between Pearson and Spearman correlation?

How do I know when to choose between Spearman's $\rho$ and Pearson's $r$? My variable includes satisfaction and the scores were interpreted using the sum of the scores. However, these scores could ...
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### What correlation coefficient and graph is appropriate with this data?

I'm not in Statistics field. I conducted the case study and collected the data as shown below I have data as shown in the table below: I would like to find correlation coefficient from this two ...
I have searched a lot, and I can only find tables that show critical values up to n=30. Can someone provide, or point me to, a simple method of estimating this value for different $\alpha$?