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Biology-Related Homework Help General Biology Topic started by: tsing_lee on Dec 11, 2021



Title: How to interpret the a pearson correlation between 2 variable
Post by: tsing_lee on Dec 11, 2021
Dear all,
I would like to ask you about how to interpret a pearson correlation relationship between 2 parameters.
Here is the graph,

(https://biology-forums.com/gallery/43/1038291_11_12_21_11_29_40.jpeg) (https://biology-forums.com/index.php?action=gallery;sa=view&id=43838)

Could I interpret this as,
A and B have strong negative relationship. When A increase, b will decrease.

then how about the spreading of points? some points are close to the line and some of that are not?
Please help me!
Thank you.


Title: Re: How to interpret the a pearson correlation between 2 variable
Post by: bio_man on Dec 11, 2021
Hi tsing_lee (https://biology-forums.com/index.php?action=profile;u=1038291),

You're right, the spread is quite substantial. It looks like there is a negative correlation between the parameters, but the R value isn't strong as you suggested. According to the chart, R is -0.57, which means it is negative moderate, not strong.

https://www.youtube.com/watch?v=bSmDdJJCP8s

According to this video, you can find the significance of the R value if you're given the raw data. But I'm assuming this graph was obtained from an article, to which they don't provide the raw data. Watch the video above to understand a little more what I mean.


Title: Re: How to interpret the a pearson correlation between 2 variable
Post by: tsing_lee on Dec 11, 2021
Hi, thank you for the suggestion.
Sometime, I doubt of interpreting the value. From the video, it was said that my result is moderate but from this source
 https://www.statisticssolutions.com/free-resources/directory-of-statistical-analyses/pearsons-correlation-coefficient/

my result is high degree.
btw, this is not obtained from article but from my assignment


Title: Re: How to interpret the a pearson correlation between 2 variable
Post by: bio_man on Dec 12, 2021
The chart presented in the video is the one I've been using for a long time, so I trust that source.

Your source doesn't suggest anything about the ranges. Are you sure you posted the correct link?

How did you find the R value? Was it given to you in the assignment? What is the assignment asking exactly?


Title: Re: How to interpret the a pearson correlation between 2 variable
Post by: jhonalbert on Dec 21, 2021
Hi,
well when we talk about Pearson's correlation, The Pearson's correlation coefficient is calculated as the covariance of the two variables divided by the product of the standard deviation of each data sample.
It is the normalization of the covariance between the two variables to give an interpretable score.