A-Level Maths: L2-04 [Scatter Graphs: The Product Moment Correlation Coefficient]
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- Опубликовано: 11 сен 2024
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Imagine not watching the end bit and doing all this in the exam for three marks xD
Lmao, i almost did
Thank you thank you thank you, you can't imagine how extremely helpful this video was for me. I've been watching your videos lately in order to learn more and more maths and your material has been very useful. Also, I couldn't find anywhere someone able to explain where pearson's formula came from. You are being very helpful in my learning and I wanted to thank you that
This is a really good and clear video
Is this linear regression? I’m not too sure I do as stats I do edexcel btw
This is part of linear regression yes - this video explain the pmcc
why have you got the sum sign with n on top and i=1 on the bottom
Because you want to add up from the 1st value up to the last (nth) value
Hello, Are we required to memorise the formula and know how to use it as it's not in the data booklet?
No, this is just showing you where it comes from. I would expect you to at most know how to find it directly on your calculator and understand what that shows.
@@TLMaths using y=a+bx and the b would be the PMCC?
If you’re using the Casio Classwiz, once you’ve typed everything in you should get a, b and r. r is the PMCC. This should help: ruclips.net/video/Xwbol8y6rPY/видео.html
@@TLMaths I understand now, Thanks.
If the variance is the square of the standard deviation. Then what is the covariance and it’s square root. Is it Sxy/n?
Is this part if AS Level maths? I cannot find it in my year 1 Edexcel book
Edexcel don't test this in their AS-Maths qualification, other exam boards do
what specification do you follow ? I do edexcel, would this be fine
I teach AQA, but these videos are designed for all four of the England specifications: AQA, Edexcel, OCR A, OCR B (MEI)
they do its in the stats/mechanics year 1 book chapter 4, you might be looking at the pure book
I can't find this in my ocr mei spec is this in it?
Yes, search for "correlation coefficient". The specification strangely says that "Learners are not required to know the names of particular correlation coefficients." even though the 2018 exam paper mentions the product moment correlation coefficient specifically!
this is A2 concept why would you put in AS videos.
This is because AQA specifically mentions it as AS in their teaching guidance. I know that Edexcel specifically doesn't mention PMCC as AS, but it is often introduced in year 1 at the stage you're introduced to regression and scatter graphs.
@@TLMaths got it. Thanks for clarifying.
Slightly confused: surely if the xi is exactly equal to the x bar, it would equal zero and doesn't matter whatever the y value is as it would be timesed by zero?
so that one value is not quite accurate?
Not sure what you mean by being not quite accurate?
Sorry, the point would still contribute to the value of r as the y-coordinate would affect ybar. Here's an example: www.desmos.com/calculator/3brppl7qtg
@@TLMaths ph right, thank you very much :)