Linked Questions

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1answer
48 views

Which correlation formula should be used when we add up many measurements of the ordinal type?

Let's say, I have two set of questions; one set is to detect depression (var1) where the response of each question is in Likert scale and another set of questions to detect hopelessness (var2) where ...
5
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1answer
380 views

How to choose a correlation measure when Pearson is close to 1 and Spearman close to -1?

I have two large datasets from nonlinear control systems. I am trying to correlate the error with the control action taken. If the error is plotted as fx and the control action as fy we end up with ...
1
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1answer
2k views

Normal Distribution for Pearson Correlation

I have read that the variables must be approximately normally distributed to apply Pearson correlation; However, I came across this answer here that they dont need to be, so I am confused about ...
5
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2answers
2k views

Pearson correlation between a variable and its square

Here is my R code to get familiarised with Pearson's correlation. I generate values of $X$ from 1 to 100, then find the correlation between $X$ and $X^2$: ...
1
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0answers
964 views

Should I use Pearson or Spearman correlation?

I have to know the correlation between 2 variables (bivariate distribution). None of them are normally distributed, so I assumed that I should run Spearman's correlation, which gave me a correlation ...
1
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2answers
997 views

Pearson and Spearman correlations [duplicate]

I'm having a problem with choosing between Pearson and Spearman correlation. I'd like to understand clearly why I should use one or the other. I have read the questions already asked here about this ...
4
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0answers
120 views

What metric to calculate correlation between average user ratings of products?

What's the best method to see if there's a strong correlation between two types of ratings on a product level (product $1, 2, \dots, n$) where each product has ratings of type '$a$' and '$b$'? For ...
0
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1answer
42 views

Correlation indexes in medicine

My father is a doctor and he asked me to find out if there is a correlation in two sets of data he collected, one concerning the age of his patients and one concerning the value of a medical exam I ...
3
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1answer
461 views

Correlation between ordinal and ordinal variables

My study is aim to show the correlation between the Prostate MRI Scoring and Prostate Pathology Gleason Scores. For prostate MRI Scoring system (PIRADS) we score lesions according to their MRI finding ...
0
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1answer
2k 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 ...
1
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3answers
148 views

What kind of statistical test is appropriate for this?

Variable X designates a group label (group 1, group 2, etc). Each group represents an amount of time spent watching TV. For example group 1 might watch TV less than an hour a week, group 2 watches 1-2 ...
3
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3answers
17k views

Correlation using Logistic Regression and Pearson

I am so sorry, I am beginner in statistic analysis, I have project using R to analyze the correlation between dependent variables and independents variables. In this case I have two dependent ...
2
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1answer
942 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. The following rule of thumb has been suggested to me: examine both Pearson and Spearman ...
9
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2answers
1k views

Why is a Pearson correlation of ranks valid despite normality assumption?

I am currently reading up on assumptions for Pearson correlations. An important assumption for the ensuing t-test seems to be that both variables come from normal distributions; if they don't, then ...
0
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0answers
57 views

Can one variable explain if another variable is preferred more than others?

I have a questionnaire consisting of 7 multi item scales. The first four multi item scale each represents if a respondent performs a giving role and the remaining 3 multi item scales each represent a ...

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